[DESCRIPTION]
[Title of Invention]
COMPUTER SYSTEM, STORAGE VOLUME MANAGEMENT METHOD, AND
COMPUTER-READABLE STORAGE MEDIUM
[Technical Field]
[OOO 11
This inveiltion relates to a computer system, a storagc volume
management method, and a computer-readable storage medium for storing a
program for controlling copy operations in a storage apparatus and, in
particular, relates to a copy control technique in a computer system.
[Background Art]
[0002]
For public or business infrastructure systems bearing social
foundations, high availability has been desired. For this reason, in the data
storage market, so-called Disastcr Rccovcry System has been demandcd that
will not lose data even if a storage apparatus holding a huge amount. of data
were destroyed by disasters, for example.
[0003]
As one of the techniques to meet to such a market request, a computer
system has been provided that backups data using a rcmotc copying
technique. This computer system stores identical data into storage
apparatuses placed at two sufficiently distant locations. When the data in
either one of ihe storage appnratusrs is updated, the update is synchronously
or asynchronously reflected to the other storage apparatus by lncans of
remote copying. Consequently, the identity of the data in the two storage
apparatuses is secured.
[0004]
To further improve the security of the data, FTL 1 discloses a storage
system that provides storage apparatuses at three sufficiently distant
locations from one other. In this computer system, the identity of the data
between the first storage apparatus to be used in normal service and the
second remote storage apparatus is secured by synchronous remote copying.
On the other hand, the identity of the data between the first storage apparatus
and the third remote storage apparatus is secured by asynchronous remote
copying.
[0005]
As a technique to effectively utilize computer resources such as CPUs,
memory devices, and storage apparatuses, system virtualization technique is
disclosed in NPL 1 and NPL 2. According to this technique, a plurality of
virtual inacliiiies (also referred to as guests) are provided on a physical
computer and the physical computer can function as if a plurality of
computers were working. This technique is utilized for effective use of
surplus computer resources or server consolidation that integrates several
hundreds of guests into a single high-performance computer.
[0006]
A virtual machine is a server environment attained by software; a
single OS runs on the virtual machine to allow applications to run.
Accordingly, for data protection, a range in which data integrity is to be
preserved is expected to include volumes used by a virtual machine. In other
words, it is desired that a system virtualization program distinguish a group of
volumes allocated to a virtual machine from a group of volumes al1ocat:ed to
other virtual machines and perform remote copying of t.he group of volumes.
[Citation List]
[Patent Literature]
[0007]
[WL 11
JP 2003-122509 A
[Non Patent Literature]
[OOOS]
[NPL I]
IBM Redbook "Introduction to the New Mainframe: z/VM Basics" (IBM Docket
No. SG24-7316-00, November 2007)
[NPL 21
IBM Manual "z/VM CP Programming Services version 6 release 1" (IBM Docket
NO. SC24-6 179-00, 2009)
[Summary of Invention]
[Technical Problem]
[0009]
Remote copying is a technique that copies data in a given volume to
another given volume. Accordingly, in the case that a storage resource
coupled to a physical computer is allocated to and used by a plurality of
virtual machines by means of the system virtualization technique described in
the background art, the association relationship between a volume and a
virtual machine in operation may be changed because or reallocation.
(00 1.01
If the change of the association relationship is ignored to continue a
copy operation, a proper copy operation is disturbed. Also, if volumes in a
storage subsystem are allocated to a plurality of virtual machines, the same
problem will occur in copying withln the storage subsystem.
[Solution to Problem]
100 111
A computer system of an emhotiimnent of the present invention
comprises a storage apparatus, a host computer which accesses volumes
provided by the storage apparatus, and a management computer. The host
computer executes a control program and a guest OS running on the control
program. The guest OS accesses one or more volumes allocated from the
storage apparatus. The storage apparatus performs copy operations of the
one or more volumes allocated to the guest 0s. One of the host computer
and the management computer executes a copy control program for
controlling copy operations by the storage apparatus. The one of the host
computer and the management computer, in accordance with the copy control
program, obtains first information indicating at least a part of one or more
volumes allocated to the guest OS at a given time from the control program.
The one of the computers, in accordance with the copy control program,
compares the first information with second information indicating at least a
part of one or more volumes having been allocated to the guest OS prior to the
given time to check for a change in volume allocation to the guest OS and
performs volume copy control for the guest OS in accordance with a result of
the checking.
[Advantageous Effects of Invention]
[OO 121
According to an embodiment of this invention, in a computer system
with virtual machines provided, proper copy operations can be achieved even
if the association relationship between a virtual machine and a volume
changes during system operation.
[Brief Description of Drawings]
[00 131
[FIG. 11
FIG. 1 is a drawing illustrating a configuratioll of a computer system in
a first embodiment.
\FIG. '21
FIG. 2 is a drawing illustrating a configuration of a storage apparatus
in the first embodiment.
[FIG. 31
FIG. 3 is a drawing illustrating a configuration of copy control
information in the first embodiment.
[FIG. 41
FIG. 4 is a drawing illustrating a configuration of copy group
information in the first embodiment.
[FIG. 51
FIG. 5 is a drawing illustrating a configuration of storage configuration
information in the first embodiment.
[FIG. 61
FIG. 6 is a drawing illustrating a configuration of guest. information in
the first embodiment.
[FIG. 7A]
FIG. 7A is an explanatory diagram of an API provided by a VM control
program in the first embodiment.
[FIG. 7B]
FIG. 7B is an explanatory diagram of an API provided by a VM control
program in the first embodiment.
[FIG. 81
FIG. 8 is a flowchart illustrating a procedure that a copy control
program prepares storage configuration information and guest information in
thc first embodiment.
[FIG. 91
FIG. 9 is a drawing illustrating a GUI in the case that the administrator
changes an attribute of guest information in the first embodiment.
IFIG. 101
FIG. 10 is an explanatory diagram of a command linc intcrfacc in thc
first embodiment.
[FIG. 111
FIG. 11 is a flowchart illustrating a procedurc that the copy control
program checks configurations and issues a command in the first
embodiment.
[FIG. 121
FIG. 12 is a flowchart illustrating a procedure that the copy control
program checks configurations and issues a command in a second
embodiment.
[Description of Embodiments]
[0014]
Hereinafter, embodiments of this invention will be described. For
c1arit.y of explanation, the following descriptions and accompanying drawings
contain omissions and simplifications as appropriate. Throughout the
drawings, like components are denoted by like reference signs and their
repetitive explallation is omitted for clarity of explanation if not necessary.
[00 151
FIRST EMBODIMENT
A first embodiment of this invention will be described with reference to
FIGS. 1 to 11. This embodiment has a feature in controlling volume copy
operations by a storage apparatus. The storage apparatus provides virtual
machines working on a host computer with volumes. A copy control program
checks for a change of volume allocation in controlling copying of a volume
allocated to a virtual machine.
[0016]
The control achieves proper copy operation in a computer system
where virtual machines work even if the association relationships between the
virtual machines and volumes are cl-langed during systcln operation. In this
cmbodirnent, input and output control 1:o and from a computer and the usage
of the storage area on the basis of volumes in a storage apparatus are the
same as those in the conventional art.
(00 171

First, a system configuration in this embodiment will be described.
FIG. 1 schematically illustrates a configuration of a computer system in this
embodiment. The system comprises a host computer 10 and a storage
apparatus 200 to be accessed by the host computer 10. The host computer
1.0 is coupled to the storage apparatus 200 by a data network 109. The
system further comprises a management computer 106, and the host
computer 100, the storage apparatus 200 and the management computer 106
are coupled to one another by a management network 110.
[00 181
The host computer 10 is accompanied by a host computer input and
output device 103, which is used for configuring at the host computer 10
mainly to manage the system operations. Similarly, the managcment
computer 106 is accompanied by a management computer input/output
device (not shown), which is used for configuring the system at the
management computer mainly to manage the operation. The management
computer 106 and the host computer 1 0 0 may be implemented in a computer.
[0019]
Typical examples of the input/output device are a monitor, a keyboard,
and a pointer device. The management computer 1.06 and the host computer
100 may be equipped with input/output devices other than these. For
example, they may be equipped with a serial interface or an Ethernet interface,
to which a moilitoring computer may be coupled. The monitoring computer
is equipped with input./output devices such as a monitor, a keyboard, and a
pointer device. A user accesses the management computer 106 or the host
computer 100 through the monitoring computer.
[0020]
For clarity of explanation, the system in this configuration is
comprised of a single storage apparatus 200 and a single host computer 100,
but this invention can be applied to a computer system comprising a plurality
of storage apparatuses and a plurality of host computers. The management
system in this configuration example includes a management computer 106,
but the management system may be composed of a plurality of computers.
One of the plurality of computers may be a monitoring computer and a
plurality of computers may deliver comparable performance to the
management computer 106 for higher speed and higher reliability in executing
management processes.
[0021]
The data network 109 is a network for data communication and is a
storage area network (SAN) in this configuration. The data network 109 may
be a network other than SAN as far as it is a network for data communication.
For example, it may be an IP network.
[0022]
The management network 110 is a network for data communication
and is an IP network in this configuration. The management network 110
may be a network other than the IP network as far as it is a network for data
communication. For example, it may be SAN. The data network 109 and
the management network 11.0 may be the same network.
[0023]
The storage apparatus 200 provides volumes which arc areas for
storing data. The configuration example of FIG. 1 exemplifies four volumes
231A to 231.D. The volumes 231.A to 231D each store data written by the
host computer 100. In this configuration example, copying is performed
between two volumes. For example, for the storage apparatus 200 to copy
data froin the volullle 23 1A to the volume 231B, the data writ:ten to t:hc volunne
231A is reflected to the volume 23 1B.
[0024]
Two volumes can constitute a copy pair. The copy pair is composed of
a copying source volume and a copying destination volume for storing a
replica of the data stored in the copying source volume. In this description,
the copying source volume is called a primary volume and the copying
destination volume is called a secondary volume. A primary volume may be
copied to a plurality of secondary volumes.
[0025]
In the configuration example of FIG. 1, two volumes that constitute a
copy pair exist in the single storage apparatus 200. Differing from this
example, volumes that constitute a copy pair may exist in separate storage
apparatuses. Volume copying for disaster recovery is typically performed
between two remote storage apparatuses.
[0026]
A copy operation performed between volumes may be synchronous or
asynchronous. A copy operation may be performed within a storage
apparatus or over a plurality of storage apparatuses. A synchronous copy
operation notifies the host computer 100 of an 110 success after writing to the
secondary volume has been completed (typically, after writing to a cache). An
asynchronous copy operation notifies the host computer 100 of an I/O
success after writing to the primary volume has been completed. 'The copy
control of this embodiment may be applied to copying among three or more
volumes. FIG. 1 shows volumes 231A to 231D in the storage apparatus 200
only. Details of the storage apparatus 200 will be described later.
[0027]
As shown in FIG. 1, the host computer 100 comprises a CPU 101, a
memory 102, an input/output device 103 such as a keyboard, a mouse, and a
monitor, a storagc I/F 104, and a rnallagement I/F 105 and they are coupled
to one anther. The storage I/F 104 is a network interface for coupling the
host computer 100 to the data network 109. The storage I/F 104 transmits
and receives data and control commands to and from the storage apparatus
200 via the data network 109.
[0028]
The management I/F 105 is a network interface for coupling the host
computer 100 to the management network 110. The management I/F 105
transmits and receives data and control commands between the storage
apparatus 200 and the management computer via the management network
110.
[0029]
The memory 102 stores virtual machine (VM) information 301A to
301.C, guest OSes 3024. and 302B, a copy control program 400, a VM control
program 107, input/output device configuration information 108, and copy
control information 500. The VM information 301A to 301C each contain
management information of virtual machines working on the host computer
100 (VM control program 107).
[0030]
The guest OSes 302.4 and 302B are each operating systems running on
different virtual machines. These include OS environmental information on
the virtual machines. The virtual machines of the guest OSes 302A and
302B run are the same as the virtual machines of the VM information 301A
and 30 lB, respectively.
(003 11
The guest OSes 302A and 302B use functions of the VM control
program 107 in writing and reading data to and from the storage apparatus
200. The guest OSes 302A and 302B send requests to the VM control
program 1.07 to read data from or write data to the volumes 23 1 A to 23 ID.
The configuration example of FIG. 1. includes two guest OSes 302A and 302U
and VM information 301A to 301C of three virtual machines, but the number
of these may be other different numbers.
[0032]
The VM control program 107 is a control program for managing the
whole virtual system. The VM control program 107 creates VM information of
each virtual machine and deletes it. The VM control program 107 includes a
function of, according to a request from a guest OS, locating a target device for
an input or output from the input/output device configuration information
108 and of inputting/outputting data to/from the storage apparatus 200 as a
part thereof. Moreover, it includes a function of allocating a real resource in
the computer system to a pair of VM information and a guest OS to lead each
virtual machine to work.
[0033]
The copy control program 40 works as a program on a virtual machine.
The copy control program 40 performs copy control according to a copy
operation procedure. Furthermore, it traiismits copy colltrol commands to a
storage micro-program 226 (refer to FIG. 2) for copy control. In response to
the requests, the storage micro-program 226 carries out operations such as
creating pairs and obtaining state information. Copy control information 50
contains information for the copy control program 40 to perform copy control.
Details of copy control will be described later.
100341
The guest OSes 302A and 302I3, the copy control program 400, and the
VM control program 107 are executed by the CPU 1 0 1. The CPU 10 1 obtains
commands included in programs on the mcmory 102 and carries out
operations correspondilig to thc commands. The CPU 101 obtains data on
the memory 102 in accordance with a command of a program and stores the
computed data into the memory 102.
100351
In the configuration of FIG. 1, at least a part of the programs and
information stored in the memory 102 may be stored in a different storage
device. For example, the host computer 100 may have an external storage
device such as a magnetic disk or a flash memory and may store a part of the
programs and information therein. In this embodiment, a data storage area
for storing data (including programs) to be processed by the CPU 101 may
have any configuration. The hardware configuration of the management
computer 106 may be the same as that of the host computer 100. In this
configuration example in which the management computer 106 is not coupled
to the data network 109, the storage I/F is not necessary.
[0036]
FIG. 2 is a block diagram schematically illustrating a configuration of
the storage apparatus 200. The storage apparatus 200 comprises a disk
apparatus 210 and a disk controller 220. The disk apparatus 210 stores
data which the host computer 100 has requested to write. The disk controller
220 controls operations of the storage apparatus 200.
[0037]
The disk apparatus 210 includes a plurality of volumes. FIG. 2
exemplifies three volumes 231A to 231C. The number of volumes depends on
the system configuration. A volume is a storage area and includes physical
storage areas of one or more storage devices. Typically, a volume is
associated with a physical memory area or a logical storage area (logical
device) in a storage device such as a hard disk drive or a flash drive. The
storage apparatus 200 may use a virtual volume. This embodiment may use
any kind of volume.
[0038]
The disk controller 220 comprises a host I/F 221, a management I/F
222, a disk I/F 223, a memory 224, and a CPU 225. Thc memory 224 holds a
storage micro-program 226 and copy pair information 227. For the memory
224 and the CPU 225, the same explanation as for the CPU 101 and the
memory 102 in the host computer 100 can be applied.
[0039]
The storage micro-program 226 is executed by the CPU 225. The
storage micro-program 226 running on the CPU 225 performs a copy
operation between a copy pair of volumes in accordance with preset control
information. The storage micro-program 226 further controls copy pairs in
response to a request from the host computer 100.
[0040]
Process examples of the copy control that is performed by the storage
micro-program 226 are creating, suspending, resynchronizing, deleting of a
pair, and obtaining of the state. The host computer 100 can request for any
one of these processes to the storage micro-program 226. These are
examples of processes in copy control and the storage apparatus 200 may
perform operations different from these.
[Ooql]
In the copy pair creating process, the storage micro-program 226 newly
creates a copy pair. The suspending process temporarily stops copying data
from the primary volume to the secondary volume. When receiving a
command for the suspending process, the storage micro-program 226 docs
not reflect change of data in the primary volume lo the secondary volume
thereafter. In an example, after the storage micro-program 226 has copied
the latest update of the primary volume to the secondary volume, it stops
copying data between the two volumes.
[0042]
The resynchronizing process synchroiiizes the primary volume with
the secondary volume to make the data in the secondary volume identical to
thc data in the primary volume. In an cxample of the rcsynchronizing
process, after the storage micro-program 226 malces two volume data ~dentical
to each other, it resumes a copy operation therebetween. The pair deleting
process releases the pair in the creating process.
[0043]
When receiving a request for the statc obtaining process, the storage
micro-program 226 sends state information on the copy pair to the host
computer 100. The state information on the volumes that constitute copy
pairs in the volumes included in the storage apparatus 200 is contained in the
copy pair information 227.
[0044]
Examples of the state of a copy pair are a copy pair state in which an
update of the primary volume is reflected to the secondary volume, a
suspended state in which a copy operation is suspended, an error state in
which copying is disabled by communication trouble, for example, a single
state in which a pair is not configured, and the like. When the storage
micro-program 226 executes the creating process, the resynchronizing
process, or the suspending process, it updates the copy pair information table
227. In addition, it may send the information on copy pair state to the host
computer 100 as the process result.
lo0451
In this configuration example, the storage micro-program 226 and the
copy pair information 227 are stored it1 the rnenlory 224 in the disk colltroller
220 but may be stored in other storage device. For example, the storage
micro-program 226 and the copy pair information 227 may be stored in a flash
memory coupled to the disk controller 220 or in a volume provided in the disk
apparatus 2 10. The storage area for storing data (including programs) to be
used by the CPU 225 may have any configuration.
[004.6]
The host I/F 221 is a network interface for coupling the storage
apparatus 200 to the data networlc 109. The host I/F 221 transmits and
receives data and control commands to and from the host computer 100 via
the data network 109.
[0047]
The management I/F 222 is a network interface for coupling the
storage apparatus 200 to the management network 110. The management
I/F 222 transmits and receives data and control commands to and from the
host computer 100 and the management computer 106 via the management
network 110. The disk I/F 223 is an interface for connecting the disk
controller 220 to the disk apparatus 210.
[0048]

Hereinafter, copy control in this embodiment will be described in detail.
FIG. 3 illustrates a configuration of the copy control information 500 in FIG. 1.
The copy control program 400 performs copy control using the copy control
information 500
[0049]
In this embodiment, information stored in a data storage area (Solexample,
copy control information 500) does not depend on data structure
and may be expressed in any data structure. For example, a data structure
appropriately selected from tables, lists, databases, and queues can store
information.
[OOSO]
As illustrated in FIG. 3, the copy control information 500 comprises
copy group information 510, pair state information 520, storage configuration
information 530, and guest information 540. The details of the copy group
51.0 will be described later with reference to FIG. 4. The details of the storage
configuration information 530 will be described later with reference to FIG. 5.
The details of the guest information 540 will be described later with reference
to FIG. 6.
I005 11
The state information which is obtained as a result of a pair state
obtaining command issued by the copy control program 400 to the storage
apparatus 200 is included in the pair state information 530. For this reason,
the pair state information 530 contains information on the respective copy
pair states of the copy pairs contained in the copy pair information 227 held in
the storage apparatus 200. The copy control program 400 refers to the copy
pair information 227 to present a user with the states of copy pairs and
performs copy control depending on the states of copy pairs.
[0052]
FIG. 4 illustrates a configuration example of copy group information
510 in FIG. 3. The copy group information 510 is information on copy groups
and, specifically, is information on primary volumes which constitute copy
groups and secondary volumes which constitute pairs with the primary
volumes. A user configures the information through the input/output device
103 or the management computer 106.
[0053]
The copying function of the storage apparatus 200 includes a grouping
function. For example, in an asynchronous copy operation, the storage
apparatus 200 sequentially selects primary volumes one by one from a target
group and performs a copy operation of the selected primary volumes
(reflecting updates in the primary volumes to the secondary volumes). The
storage apparatus 200 performs copying for keeping integrity; for example, it
copies data to the secondary volumes in the order of writing to the volunles in
the group.
[0054]
A copy group is preferably composed of all of the primary volumes
allocated to a virtu~lm achine. The storage apparatus 200 performs copy
operations for each copy group. I t achieves efficient copy control and secure
preservation of data integrity within the copy group. The number of primary
volumes included in a copy group may be one.
[0055]
As illustrated in FIG. 4, the copy group information 510 comprises a
group identifier 5101, a copying type 5102, primary volume identifiers 5103,
and secondary volume identifiers 5104 for each copy group. The example of
FIG. 4 shows three copy groups G1 to G3; the item names of the group G1 are
denoted with reference signs for exemplification purposes.
[0056]
A group identifier 5 10 1 identifies a copy group. A copying type 5 102
identifies the type of copy mode, such as synchronous copying and
asynchronous copying. A primary volume identifier 5103 and a secondary
volume identifier 5104 identify a primary volume and a secondary volume,
respectively, which constitute a copy pair. The volume identifiers identify the
corresponding storage apparatus and volumes in the storage apparatus.
[0057]
In the example shown in FIG. 4, there exist three copy groups G1 to G3.
For example, there are two pairs in the copy group GI. One of the pairs
consists of a primary volume with a volume identifier A001 and a secondary
volume with a volume identifier ROO].. The other pair consists of a primary
volume with a volume identifier A002 and a secondary volulllc with a volume
identifier B002.
[0058]
FIG. 5 illustrates a configuration example of the storage configuration
information 530 in FIG. 3. The storage configuration information 530 is
information on volumes in storage apparatuses (disk subsystems).
Spccifically, the storage configuration information 530 comprises a disk
subsystem number 531, volume numbcrs 532, volume identifiers 533, and
volume labels 534 for each disk subsystem. FIG. 5 exemplifies configuration
information of two storage apparatuses (disk subsystems). The storage
configuration information 530 associates these with one another. Although
FIG. 1 exemplifies one storage apparatus 200, the computer system in this
embodiment may comprise any number of storage apparatuses.
[0059]
A disk subsystem number 53 1 is an identifier of a storage apparatus.
A volume number 532 is information for identifying a volume in the storage
apparatus. Volume identifiers 533 are the same as the volume identifiers in
the copy group information 510.
[0060]
A volume label 5304 is an identifier for identifying a volume appointed
by a user. Volume identifiers and volume labels are contained in the
input/output device configuration information 1.08. The host computer 100
can learn the volume identifier, the volume label, the storage apparatus, and
the volume number of a certain volume with reference to the storage
configuration information 530.
[006 11
FIG. 6 illustrates a configuration example of the guest information 540
in FIG. 3. FIG. 6 exemplifies information on a guest. As shown in FIG. 1, in
a configuration in which a plurality of guests (virtual machines) are working,
the guest information 540 includes information on the plurality of guests.
The guest information 540 comprises a guest number 541, volume identifiers
542, volume labels 543, and attributes 544 for each guest.
[0062]
A guest number 541 is information for identifying a virtual machine
which is a guest. A set of a volume identifier 542, a volume label 543, and an
attribute 544 is information on a volume allocated to the virtual machine
having a guest number 541 associated therewith. The guest information 540
indicates 1:he volume identifier, volume label and attribuk of each of the
volumes allocated to each guest.
[0063]
The volume identifiers 542 are the same as the volume identifiers in
the copy group information 510 and in the storage configuration information
530. The volume labels 543 are the same as the volume labels in the storage
configuration information 530. An attribute 544 is information for indicating
whether the allocation of the associated volume to the guest may be changed
or not during system operation. The attribute information will be described
later in detail.
[0064]

Hereinafter, preparing (obtaining) of the copy control information 500
to be used by the copy control program 400 will be explained. The copy
colltrol information 500 is prepared in a system development phase or a
system management phase. Specific information may be updated in a
system operation phase. This process uses an API (Application Program
Interface) in the VM control program 107. Hence, the API will be explained
first.
[0065]
FIGS. 7A and 7B are explanatory drawings of an API which is provided
to a user or a program by the VM control program 107. The VM control
program 107 refers to the input/output device configuratioll information 108
and the VM information 301 according to an input from the copy control
program 400 to obtain necessary information. Then, it sends the obtained
information to the copy control program 400.
[0066]
An input to the API includes, as illustrated in FIG. 7A, fields of a
command 701, a target volume identifier 702, and a target guest number 703.
In this example, the command 701 is a commalid to obtain volume
information. The target guest 703 indicates a target guest for obtaining the
volume information. The target volume identifier 702 is an identifier to
identify a target volume, on which the command requests to obtain
information, in the volumes allocated to the target guest 703.
[0067]
An output in response to the input includes, as illustrated in FIG. 7B, a
volume label 704 and an attribute flag 705. The volume label 704 indicates
the volume label allocated to the volume identifier appointed by the input.
The attribute flag 705 indicates the allocation mode of a volume appointed by
the input to a virtual machine indicated by the guest number.
I00681
Specifically, in this embodiment, a volume has either one of two
attributes. One attribute is "possessed" and the other one is "temporary".
The attribute flag 705 indicates "possessed" or "temporary"
(possessed/ temporary).
[0069)
A virtual machine (guest) to which a volume having the attribute
-possessed" has been allocated keeps the right to possession of the volume.
While the virtual machine is working, it is prohibited to change the allocation
of the volume to the virtual machine and the association relationship
therebetween will not be changed. The allocation of a volume having the
att~ribute" temporary" may be canceled in accordance with an instruction of a
user while the virtual machine is working. The user (the computer system)
can reallocate the volume whose allocation to a certain virtual il~achineh as
been canceled to another volume. In this way, the right to possession of a
volume having the attribute "temporary" may be changed while virtual
machines are working.
[0070]
I-Iereinafter, the preparing (obtaining) proccss of the copy control
information 500 which is used by the copy control program 400 in its copy
control will be explained in detail. The copy control program 400 refers to the
copy group information 510, the storage configuration information 530, and
the guest information 540 to check for change of volume allocation in the copy
control process. Hereinafter, the preparing of the information will be
described in detail.
[007 11
As explained with reference to FIG. 4, the copy group information 510
is configured by a user (including by a program created by a user) through the
inputfoutput device 103 or the management computer 106. Hereinafter, the
preparing process of the storage configuration information 530 shown in FIG.
5 and the guest information 540 shown in FIG. 6 will be described in detail.
[0072]
PIG. 8 is a flowchart illustrating a procedure of preparing the storage
configuration information 530 and the guest information 540 executed by the
copy control program 400. The copy control program 400 uses the API
illustrated in FIG. 7 to perform this process.
(00731
The copy control program 400 obtains a list of guest numbers (the
numbers of virtual machines) using the API provided by the VM control
program 107 (S801). The VM control program 107 can VM information 301C
to prepare this list with reference to the VM information 301A.
(00741
Next, it obtains information on virtual machines identified by the guest
numbers in the list obtained at the step 801. Specifically, the copy control
program 400 determines whether or not the information obtaining process at
step 803 and step 804 has been completed for each guest number (S802). I f
the determination at the step 802 is true, the copy control program 400 ends
the process.
[0075]
I f the determination at the step 802 is false, it continues the process to
obtain the volume information on a virtual machinc. At step 803, the copy
control program 400 obtains the information on the volumes allocated to the
virtual machine and prepares the guest information 540.
[0076]
Specifically, it specifies a guest number and all possible values which
the volume identifiers intended to be managed may take in the API shown in
FIG. 7. As a result, the copy control program 400 obtains information on the
volumes which have been allocated to the specified virtual machine and are
intended to be included in the specified management target.
[0077]
The copy control program 400 adds the obtained volume identifiers
702 to the guest information 540 of the associated guest number 5401 as
entries of the volume identifier 5402 (the data indicating the volume
identifiers). In the same way, it adds the obtained volume labels 704 as
entries of the volume label 543 and the attribute flags 705 as entries of the
attribute 544 to the guest information 540.
(00781
Next, at step 804, the copy control program 400 obtains information on
the storage apparatus (the disk subsystem) associated with the volumes
allocated to the target virtual machine from the storage apparatus and
prepares the storage configuration information 530. If the computer system
includes a plurality of storage apparatuses, the copy control program 400
issues a command to obtain information to each storage apparatus.
(00791
The process of obtaining information from the storage apparatus 200
will be explained in detail. The copy co~ltropl rogram 400 issues a command
to obtain information to the storage apparatus 200 while specifying each entry
of the volume identifiers 5402 included in the guest information 540 obtained
at the step 803.
[OOSO]
The copy control program 400 obtains information on the volumes
included in the storage apparatus 200 from the storage apparatus 200. It
adds the disk subsystem number of the storage apparatus 200 to the storage
configuration information 530 a s an entry of the disk subsystem number 530 1.
Furthermore, it adds an entry of the volume identifier 5402, an entry of the
associated volume number 5302 and an entry of the associated volume label
5403, the information of which has been able to be obtained from the storage
apparatus 200.
[0081]
The copy control program 400 executes the steps 803 and 804 on all
the guest numbers obtained at the step 801 (S802 to S804). When the steps
803 and 804 on all the guest numbers have been completed, the process for
preparing the storage configuration information 530 and the guest
information 540 ends.
[0082]
As explained with reference to FIG. 7B, the attribute of a volume is to
define the relationship between a virtual machine and a volume. Accordingly,
it is preferable that a user (or a program created by a user) can set the
attribute of each volume in accordance with the purpose of the computer
system. FIG. 9 shows an example of a graphical user interface (GUI) to
change the attribute 544 in the guest information 540 by a user's input using
an input/output device in the management computer 106.
[0083]
The user (administrator) can set the attribute of a volume through the
GUI shown in FIG. 9. Specifically, the user specifies the volume whose
attribute the user wants to change with the guest umber of tlie virtual
machine and the volume identifier or the volume label and enters a new
attribute at the corresponding entry field of a new configuration. If a user
click of the execution button for updating the configuration reflects the new
attribute to the volume.
[0084]

Hereinafter, a flow of the copy control process using the copy control
information 500 by the copy control program 400 will be explained. When
the copy control program 400 receives a copy control command from a user
(including a program), it performs a copy control process in accordance with
the command.
[0085]
FIG. 10 is an explanatory diagram of a command line interface
provided by the copy control program 400 to a user (an input via an input and
output device or a script program). The command line interface includes
fields of a command 1001, a target 1002, and an option 1003.
[0086]
In the field of the command 1001, a copy control command; such as
"create a pair" or "obtain the state", is described. In the example of PIG. 10,
any one of the commands of "create a pair", "suspend, "resynchronize", and
"obtain the state" is described. In the field of the target 1002, a group or a
pair which is to be the target of the command is described. 111 the example of
FIG. 10, any one of the three groups G1 to G3 is described.
[0087]
In the field of the option 1.003, an option necessary to process the
command is described, if any. In the option field 1003 in the example of FIG.
10, checking for the existence of a volume having the attribute "temporary" is
indicated. Thc figurc in thc parenthesis in thc field indicates the guest
number. These corrirnands and parameters niay adopt various patterns in
accordance with the copying function of the storage apparatus 200 other than
those in the configuration illustrated by FIG. 10.
[0088]
Next, a flow of a process of issuing command to the storage apparatus
200 by the copy control program 400 will be described. In the following
process, it is assumed that a primary volume allocated to a virtual machine
(guest) and a secondary volume associated therewith constitute a copy group.
[0089]
FIG. 11 is a flowchart illustrating a procedure of the issuing of a
command. The copy control program 400 receives an instruction about copy
control such as "suspend" or "obtain the state" (S1101). It determines
whether or not the option "check for a volume having the attribute
'temporary'" is described in the received command line input (S1102). If the
determination at the step 1102 is true, the copy control program 400 performs
the steps as follows. It checks the appointed copy group for a volume having
the attribute "temporary" (S1103).
[0090]
Specifically, the copy control program 400 re-obtains the guest
information 540 of the guest number appointed it1 the option together with
"check for a volume having the attribute 'temporary'". The copy control
program 400 can re-obtain (re-prepare) the guest information 540 according
to the procedure illustrated with reference to FIG. 8.
[0091]
The copy control program 400 compares the newly obtained guest
information 540 and the copy group information 510 of the copy group
appointed by the command. Specifically, it compares the list of identifiers of
the volumes having the attribute "temporary" included in the guest
information 540 and the list of the identifiers of the primary volumes having
the attribute "temporary" includcd in thc copy group informatioil 510.
[0092]
The copy control program 400 further compares the newly obtained
guest information 540 and the storage configuration information 530.
Specifically, it compares the volume labels associated with the identifiers of
the volumes having the attribute "temporary" between the guest information
540 and the storage configuration information 530.
[0093]
Next, the copy control program 400 determines whether or not any
discrepancy exists between the current state indicated by the newly prepared
guest information and the definition in the preliminarily prepared copy control
information 500 as a result of the checking at the step 1103 (S1104).
[0094]
Specifically, if the volume identifiers of the primary volumes contained
in the two lists are different, the copy control program 400 determines that the
current volume allocation to the target virtual machine is different from (does
not agree with) the previous configuration registered in the copy control
information 500 (T at S1104).
[0095]
Meanwhile, if the volume labels are different, the copy control program
400 determines that the current volume allocation of the target virtual
machine is different from (does not agree with) the previous configuration
registered in the copy control information 500 (T at S1104). If the primary
volume identifiers and the volume labels agree with the previous information,
it determines the current configuration agrees with the setting definition (F at
S1104).
[0096]
If the determination result at the step 1104 is true, the copy control
program 400 performs the following steps. It determines whether the
indicated command is 1:o create a copy volumc pair or not (Sl105). If the
determination result at the step 1105 is true, it performs error handling and
ends the copy control command issuing process (S1106). A notice of
cancelation of command execution in the error handling corresponds to a
warning.
[0097]
If the determination result at the step 1105 is false, the copy control
program 400 outputs a warning indicating a discrepancy (S1107) and
proceeds to step 1108 to continue to perform the next step. If the
determination result at the step 1102 is false, if the determination result at the
step 1104 is false, or when the process at the step 1107 has been completed,
the copy control program 400 issues a command to the storage apparatus 200
in accordance with the received command (S1108) to end the process. If the
guest information 540 does not include a volume having the attribute
"temporary", the determination result at the step 1104 should be false.
[0098]
As described above, this embodiment checks for a change in the
association relationship between virtual machines and volumes. Therefore,
in a computer system in which the association relationship between volumes
and virtual machines changes in operation because of reallocation,
appropriate copy operation can be achieved. Besides, in data protection by
means of volume copying in a virtual enviroilment in which a number of
virtual machines work, copy operations including a volume whose allocation
may be changed from a virtual machine to another virtual machine can be
achieved.
[0099]
This embodiment, as explained with reference to FIG. 11, instructs to
check, by (the option of) a copy control command, the allocated volumes to the
virtual machine to which its target volume has been allocated. Accordingly, it
is unnecessary to check the association relationship with (the allocation to)
virtual machines on all of the volumes, so the amount of processes can be
reduced. Furthermore, since it checks on the virtual machine to which the
target volume of the copy control command belongs, volumes (virtual
machine) to be checked can be selected properly.
[OlOO]
In computer system operation, a volume may sometimes be
temporarily allocated to a virtual machine for the contents to be checked. An
operator (user) immediately reallocates the volume allocated to a virtual
machine to another virtual machine. In this embodiment, since the user can
instruct to check the volume allocation by a copy control command, this
embodiment can avoid detecting a state in the course of manipulation by the
operator but can check on the established steady association relationship.
[0101]
Although the volume allocation check can preferably be instructed by a
copy control command as described above, the copy control program 400 may
perform the check of allocation relationship on all or a part of the volumes in
response to a trigger event other than the copy control command or at a preset
time. In such a configuration, too, it is preferable to obtain new guest
information (information on the volumes allocated to virtual machines) in
checking the volume allocation.
[01.02]
This embodiment provides a volume with an attribute of allocation
("possessed" or "temporary") to a virtual machine. Since it can fur the
allocation of a desired volume to a virtual machine, unintentional lost of the
volume data can be effectively prevented. As explained with reference to PIG.
11, this embodiment checks volumes having the attribute "temporary" only, so
the amount of process in checking the volume allocation can be reduced.
[O I 031
The cornpstte~-s ystclri may treat all oC Ole volumes as volumes having
the same attribute without assigning different attributes to volumes. The
allocated virtual machines may be changed during system operation for all of
the volumes. The copy control program 400 checks all of the volumes which
have been allocated to virtual machines. The computer system may provide a
volume with an attribute out of three or more kinds of attributes.
[0104]
The process explained with reference to FIG. 11 checks for a
discrepancy between volume lists (a difference in allocated volume) and a
discrepancy between volume labels. In this way, it is preferable to check on
at least two points for data protection, but the process may check on either
one or other point than these to perform copy control.
[O 1051
As described above, in a preferred configuration, this embodiment
defines a group composed of all volumes allocated to a virtual machine and
performs a copy operation within the group as a unit. This configuration
achieves preservation of data integrity and improvement in convenience in
copy operations among the volumes in a virtual machine.
[0 1061
Since this embodiment checks volume allocation within a copy group,
unnecessaly copying of a volume with its allocation canceled or interruption of
a copy operation caused by a volume with its allocation canceled can be
prevented. Furthermore, copying a newly allocated volume can be performed
properly.
[0107]
It is preferable that the volumes allocated to a virtual machine
constitute a copy group, but this invention is applicable to other configuration.
For example, the volumes allocated to a virtual machine do not need to be the
same as the volumes of a copy group. Otherwise, the computer system does
not need to use copy groups.
[0 1081
In such configurations, the copy group information 510 cannot be
used. For example, the copy control program 400 can detect a change in
volume allocation to a virtual machine by comparing previous guest
information with newly prepared guest information.
[0 1091
As in the above-described configuration, it is preferable that the copy
control program 400 check all of the volumes having the attribute "temporary"
in the volumes allocated to a virtual machine. This process properly achieves
both of reduction in the amount of process and data protection by checking for
a change of volume allocation. In particular, if the copy control command
appoints a copy group, all the volumes having the attribute "temporary" are
the target of the copying, so it is important to check those volumes.
(01 101
The copy control program 400 may check for a change of allocation on
only a part of the volumes which have been allocated to a virtual machine and
have the attribute "temporary". Specifically, if the copy control command
appoints a part of the pairs in a copy group, the copy control program 400 may
check for a change of allocation on the pairs only. Conversely, it may include
other volumes having the attribute "temporary" which the copy control
command does rlot appoint into the target of the check for a change of
allocation.
(0 1. 1. 11
As indicated in FIG. 11, it is preferable that the computcr system
output a warning when volume allocation to a virtual machine has been
changed. This allows a user to learn the change of volume allocation and the
user can take appropriate responses. The method and the content of the
warning depend on the design. The method of warning is arbitrary, but
preferably, the warning indicates the volume with its allocation changed.
[0112]
As indicated in FIG. 11, in this embodiment, if a copy control command
is creation of a copy pair and volume allocation to a virtual machine has been
changed, the copy control program 400 does not issue the command to the
storage apparatus 200 and terminates the process. The operation can
prevent unintended data corruption in a secondary volume caused by creating
a new copy pair.
[0113]
The process illustrated in FIG. 11 issues a command other than
creating of a copy pair. However, it may cancel a part or all of the commands
other than creating of a copy pair. If the design allows, the copy control
program 400 may issue a command of creating a copy pair.
[0114]
In this embodiment, the host computer 100 issues a copy control
command to the copy control program 400, but instead, the management
computer 106 may do it. The copy control program 400 may run on the
management computer 106 instead of the host computer 100. These
explanations added to this embodiment may be applied to other embodiment
described below.
101 15)
SECOND EMBODlMENT
The first embodiment uses a grouping function included in the copying
function of the storage apparatus 200 in copy operations in units of copy
group. The host computer 100 registers volume pairs to constitute a copy
group in the storage apparatus 200 and the storage apparatus 2000 gathers
the volunles in a registered copy group to perform a copy operation.
[OI 161
This embodiment uses a copying function of the storage apparatus 200
in units of copy pair. The copy control progran? 4-00 defines a copy group
which consists of one or more copy pairs and treats a copy group as an object
of operation. The configuration of this embodiment is the same as that of the
first embodiment except for the processes shown in the flowchart of FIG. 12.
[0117]
FIG. 12 is a flowchart illustrating a procedure of issuing a command by
the copy control program 400 in this embodiment. This copy control program
400 obtains instructions concerning copy control, such as suspending or
obtaining the state of pair (S1201). Next, it determines whether or not the
received command line input indicates the option of "check for a volume
having the attribute 'temporary"' (S1202).
[0118]
It the determination at the step S1202 is true, the copy control
program 400 performs the following processes. It checks the appointed copy
group for a volume having the attribute "temporary" (S1203). Specifically,
the copy control program 400 re-obtains the guest information 540 of
appointed by the option together with "check for a volume having the attribute
"temporary" and compares the obtained list of identifiers of the volumes and
the list of the identifiers of the primary volumes having the attribute
"temporary" included in the copy group information 510 corresponding to the
copy group number appointed by the copy control command.
101 191
The copy control program 400 determines whether or not any
discrepancy exists between the definition in the copy group information 510
and the current state indicated by the re-obtained guest inforlnatio~l 540 in
the result of the check at S1203 (S1204). If the determination at the step
1204 is true, it performs the following steps.
[O 1201
The copy control program 400 determines whether the indicated
command is crca1:itlg of'a copy pail- or not (S1205). If thc determination at the
step 1205 is true, it performs error handling (S1206) and terminates the copy
control command issuing process. If the determination at the step S1205 is
false, it outputs a warning indicating that there is a discrepancy (S1207) and
proceeds to step S1208.
[0121]
At the step 1208, the copy control program 400 determines whether
the list of the primary volume identifier included in the copy group information
510 includes, in the check at the step 1203, a volume identifier different from
those in the volume identifier list included in the re-obtained guest
information 540.
[0122]
If the determination at the step 1208 is true, the copy control program
400 issues a copy control command only on the volume identifiers included in
the re-obtained guest information 540 to the storage apparatus 200 (S1209)
since it might operate volumes allocated to other guest.
[0 1 231
If the determination at the step 1202 is false, if the determination at
the step 1204 is false, or if the determination at the step 1208 is false, the copy
control program 400 issues a copy control command for all of the volumes in
the copy group to the storage apparatus 200 as requested (S1210) and
terminates the process.
[0 1 24.1
This embodiment changes its behavior in the case that the scope of the
definition of the copy group information includes more volumes than the
volumes allocated to the associated virtual machine, in addition to the case
that the received command is creating of a copy pair. This configuration
prevents, when a copy pair belongs to two copy groups, an operation for one of
the copy groups from stopping a pair created in the other copy group, and
other operational problems in copy operations.
[0125]
As set forth above, this invention has been explained in detail with
reference to the accompanying drawings. However, this invention is not
limited to such specific configurations but includes various modifications and
equivalent configurations within the scope of the accompanying claims.
[0 1261
For example, in the above-described embodiments, a configuration in
which a plurality of virtual machines of guests are provided on a VM control
program of a hypervisor has been described as an implementation example of
system virtualization technology. Unlike this, the computer system may
operate a virtualized program on a normal OS to provide a plurality of virtual
machines of guests on the virtualized program. This invention may be
applied to a computer system either of a mainframe system and an open
system.
[0 1271
The program is executed by a processor (for example, a CPU) to
perform predetermined processes using a memory and a communication port
(a communication control device). Accordingly, the sentences having their
subjects of "program" in the descriptions of the above embodiments may be
replaced with the sentences having the subjects of "processor". Alternatively,
the proccsscs cxccuted by a program are the processes executed by the
computer or information processing apparatus on which the program runs.
For example, the copy control program is a copy controller for controlling
copying; a CPU and a computer worlring according to the copy control
program are also copy controllers.
[O 1281
A part or the whole of a program may be implemented by dedicated
hardware. The program can be installed in computers by a program
clist.rib~tlions erver or a cornputei- readable non-volatile storage medium and
can be stored in a storage medium in an external non-volatile storage
apparatus of each computer.
[Industrial Applicability]
[0129]
This invention can be applied to copy operations of volumes which
have been allocated to virtual machines.

[CLAIMS]
[Claim 11
A computer system comprising:
a storage apparatus;
a host computer which accesses volumes provided by the storage
apparatus; and
a management computer, wherein:
the host computer executes a control program and a guest OS running
on the control program;
the guest OS accesses one or more volumes allocated from the storage
apparatus;
the storage apparatus performs copy operations of the one or more
volumes allocated to the guest OS;
one of the host computer and the management computer executes a
copy control program for controlling copy operations by the storage apparatus;
the one of the host computer and the management computer, in
accordance with the copy control program, obtains first information indicating
at least a part of one or more volumes allocated to the guest OS at a given time
from the control program; and
the one of the computers, in accordance with the copy control program,
compares the first information with second information indicating at least a
part of one or more volumes having been allocated to the guest OS prior to the
given time to checlc for a change in volume allocation to the guest OS and
perfor~v~o~11s1 mec opy control for the guest OS in accordance with a result of
the checking.
[Claim 21
A computer system according to claim 1, wherein the one of the
computers receives a copy control command for a volume allocated to the
guest OS and performs the checking in response to the receipt of the copy
control command.
[Claim 31
A computer system according to claim 2, wherein the one of the
computers obtains the first information in response to the receipt of the copy
control command.
[Claim 41
A computer system according to claim 3, wherein the one of the
computers performs the checking in a case that the copy control command
instructs the checking.
[Claim 51
A computer system according to claim 4, wherein:
attributes available for a volume allocated to the guest OS includes a
first attribute indicating that the allocation to the guest OS is allowed to be
changed in operation and a second attribute indicating that the allocation to
the guest OS is not allowed to be changed in operation; and
the first information and the second information are configured with
information on all of the volumes which are allocated to the guest OS and have
the first attributes.
[Claim 61
A computer system according to claim 5, wherein:
a copy group which is composed of all of t:he volumes allocated to the
guest OS and is a unit of copy operation in the storage apparatus is defined;
and
the second information is information on the copy group.
[Claim 7)
A computer system according to claim 6, wherein the one of the
computers determines at least one of existence or non-existence of over or
short in volume and existence or non-existence of discrepancy in volume label.
[Claim 81
A computer system according to claim 7, wherein, if the received copy
control command is creating a copy pair and the determination results in
existence, the one of the computers performs error handling without issuing
a copy control command of creating a copy pair to the storage apparatus.
[Claim 91
A computer system according to claim 5, wherein:
a copy group which is composed of all of the volumes allocated to the
guest OS and is a unit of operation for the one of the computers is defined; and
the second information is information on the copy group; and
the one of the computers excludes a volume which is included in the
copy group and is not included in the first information from a target in a case
that the one of the computers issues a copy control command for the copy
group to the storage apparatus.
[Claim 101
A method of managing volumes in a storage apparatus in a computer
system comprising a host computcr which executes a control program and a
guest OS running on the control program, the storage apparatus which
provides the guest OS with one or more volumes and executes copy operations
of the one or more volumes, and a management computer, thc method
comprising:
executing, by one of the host computer and the management computer,
a copy control program for controlling copy operations by the storage
apparatus;
obtaining, by tlle one of the computers in accordance wit11 the copy
control program, first information which indicates at least a part of one or
more volumes allocated to the guest OS from the control program at a given
time;
comparing, by the one of the computers in accordance with the copy
control program, the first information with second information which
indicates at least a part of one or more volumes having been allocated to the
guest OS prior to the given time to check for a change in volume allocation to
the guest 0s; and
controlling, by the one of the computers in accordance with the copy
control program, volume copying for the guest OS in accordance with a result
of the checking.
[Claim 1 I]
A method according to claim 10, wherein the one of the computers
receives a copy control command for a volume allocated to the guest OS,
obtains the first information in response to the receipt of the copy control
command, and performs the checking.
[Claim 121
A method according to claim 10, wherein:
attributes available for a volume allocated to the guest OS includes a
first attribute indicating that the allocation to the guest OS is allowed to be
changed in operation and a second attribute i~ldicatingth at the allocdtion to
the guest OS is not allowed to be changed in operation; and
the one of the computers performs the checking on volumes having the
first attribute.
[Claim 131
A computer-readable storage medium for storing a program for
controlling volume copy operations by a storage apparatus in a computer
system comprising a host computer that executes a control program and a
guest OS running on the control program and a storage apparatus that
provides the guest OS with one or more volumes, wherein a process performed
by the host computer in accordance with the programs comprises:
obtaining first information indicating at least a part of one or more
volumes allocated to the guest OS from the control program at a given time;
and
comparing the first information with second information indicating at
least a part of one or more volumes having been allocated to the guest OS prior
to the given time to check for a change in volume allocation to the guest OS
and perform volume copy control for the guest OS in accordance with a result
of the checking.
[Claim 141
A computer-readable storage medium according to claim 13, wherein:
a copy group which is composed of all of the volumes allocated to the
guest OS and is a unit of copy operation in the storage apparatus is defined;
and
the second information is information on the copy group.
[Claim 151
A computer-readable storage medium according to claim 13, wherein
the process includes determining at least one of existence or non-existence of
over or short in volume and existence or non-existence of discrepancy in
volume label in the comparing the first iilfoi-illatioi~ with the second
information.