Patent Publication Number: US-2023153007-A1

Title: Information processing system and method

Description:
CROSS-REFERENCE TO PRIOR APPLICATION 
     This application relates to and claims the benefit of priority from Japanese Patent Application number 2021-185914, filed on Nov. 15, 2021 the entire disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     The present invention generally relates to information processing and, for example, specifically relates to information processing for supporting the migration of a computer and a volume. 
     Known is a technology for migrating, to a cloud environment (predominantly a public cloud environment), a computer using a volume in a first storage system (for example, on-premises storage system) and a volume used in the computer (volume in the first storage system). According to this type of technology, migration of a computer or a volume to a cloud environment is performed using a cloud migration tool. A cloud migration tool is a typically a system provided by a cloud environment vendor. 
     A computer is migrated as a computer instance to a cloud computer service, and a volume is migrated to a predetermined default cloud storage service that can be accessed by a cloud computer service (typically, a cloud storage service provided by a cloud environment vendor). 
     As volumes used by a computer, there are a system volume (this may also be referred to as a boot volume) as a volume for storing an image of an OS (Operating System) of a computer, and a data volume as a volume for storing data input to or output from a computer. 
     There may be users who wish for at least the migration destination of a data volume to be a second storage system that is different from the default cloud storage service. A second storage system is typically a storage system which is superior in reliability or function in comparison to a default cloud storage service. Specifically, for example, a second storage system is a cloud storage service of the same cloud environment but a cloud storage service developed by a storage vendor and not by a cloud environment vendor. 
     According to the technology disclosed in NPTL 1, the migration destination of a data volume may be a cloud storage service as a second storage system (migration destination storage system) provided by a storage vendor of a first storage system (migration source storage system), rather than a default cloud storage service. A cloud migration tool is not used in the migration of a data volume from a first storage system to a second storage system, and an original tool provided by the storage vendor; specifically, a so-called remote copy function of migrating a volume between storage systems, is used. 
     CITATION LIST 
     Non-Patent Literature 
     [NPTL 1] Pure Cloud Block Store vVol VM Migration to AWS with CloudEndure https://support.purestorage.com/Pure_Cloud_Block_Store/Pure_Cloud_Block_Store_vV ol_VM_Migration_to_AWS_with_CloudEndure 
     SUMMARY 
     Nevertheless, with the technology disclosed in NPTL 1, a first storage system as a migration source of a data volume to be migrated to a second storage system is limited to a storage system having compatibility with a second storage system. Storage systems that do not have compatibility with a second storage system are, for example, as follows. 
     A storage system provided by a storage vendor that is different from a storage vendor of a second storage system.
 
A storage system of a different type (for example, different model) than a second storage system as a storage system provided by a storage vendor of a second storage system.
 
     An information processing system communicable with a cloud computer, a first storage system and a second storage system is constructed. When migrating a computer instance to a cloud computer and migrating data used by the computer instance from the first storage system to the second storage system, the information processing system causes a migration tool of the cloud computer to migrate, from the first storage system to the cloud computer, a system volume storing an image of an OS (Operating System) for configuring the computer instance to be migrated, and a data volume storing data used by the OS. The information processing system causes the second storage system to create a mapping volume, which has been mapped to the data volume migrated to the cloud computer with the migration tool of the cloud computer, in the second storage system, and sets a path of data input/output from the computer instance to the mapping volume in the computer instance. 
     Even if a first storage system does not have compatibility with a second storage system that is different from a default cloud storage service that can be accessed by a cloud computer service as a migration destination of a computer instance, a volume in the first storage system can be migrated to the second storage system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram showing an overview of the system migration according to the first embodiment. 
         FIG.  2    is a diagram showing the configuration of the cloud environment after completion of the cloud migration processing. 
         FIG.  3    is a diagram showing the configuration of the cloud environment after creation of the mapping volume. 
         FIG.  4    is a diagram showing the migration of data from the mapping volume to the target volume. 
         FIG.  5    is a diagram showing a flow of the system migration processing. 
         FIG.  6    is a diagram showing a flow of the migration processing. 
         FIG.  7    is a diagram showing a flow of the start processing of the cloud migration processing. 
         FIG.  8    is a diagram showing a flow of the completion confirmation processing of the cloud migration processing. 
         FIG.  9    is a diagram showing a flow of the decision processing of the external connection method. 
         FIG.  10    is a diagram showing a flow of the path switching processing. 
         FIG.  11    is a diagram showing an overview of the system migration according to the second embodiment. 
         FIG.  12    is a diagram showing an overview of the system migration according to the third embodiment. 
         FIG.  13    is a diagram showing an overview of the system migration according to the fourth embodiment. 
         FIG.  14    is a diagram showing an overview of the system migration according to the fifth embodiment. 
         FIG.  15    is a diagram showing an overview of the system migration according to the sixth embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     In the following explanation, “interface device” may be one or more interface devices. The one or more interface devices may be at least one of the following. 
     One or more I/O (input/Output) interface devices. An I/O (input/Output) interface device is an interface device to at least one of either an I/O device or a remote display computer. An I/O interface device to a display computer may be a communication interface device. At least one I/O device may be a user interface device, for example, one of either an input device such as a keyboard or a pointing device, or an output device such as a display device.
 
One or more communication interface devices. One or more communication interface devices may be one or more same type of communication interface devices (for example, one or more NICs (Network Interface Cards)) or two or more different types of communication interface devices (for example, an NIC and an HBA (Host Bus Adapter)).
 
     Moreover, in the following explanation, “memory” is one or more memory devices as an example of one or more storage devices, and is typically a primary storage device. At least one memory device in a memory may be a volatile memory device or a nonvolatile memory device. 
     Moreover, in the following explanation, “persistent storage device” may be one or more persistent storage devices as an example of one or more storage devices. A persistent storage device may typically be a non-volatile storage device (for example, auxiliary storage device), and may specifically be, for example, an HDD (Hard Disk Drive), an SSD (Solid State Drive), an NVME (Non-Volatile Memory Express) drive, or an SCM (Storage Class Memory). 
     Moreover, in the following explanation, “storage device” may be at least a memory or a memory of a persistent storage device. 
     Moreover, in the following explanation, “processor” may be one or more processor devices. While at least one processor device may typically be a microprocessor device such as a CPU (Central Processing Unit), or may be another type of processor device such as a GPU (Graphics Processing Unit). At least one processor device may be a single-core processor device or a multi-core processor device. At least one processor device may be a processor core. At least one processor device may be a processor device in a broad sense such as a circuit (for example, FPGA (Field-Programmable Gate Array), CPLD (Complex Programmable Logic Device) or ASIC (Application Specific Integrated Circuit)) as an aggregate of gate arrays based on a hardware description language which performs a part or all of the processing. 
     Moreover, in the following explanation, while a function may be explained using an expression such as “yyy unit”, the function may be realized by one or more computer programs being executed with a processor, or realized by one or more hardware circuits (for example, FPGA or ASIC), or realized based on a combination thereof. When a function is realized by a program being executed with a processor, since predetermined processing will be performed using a storage device and/or an interface device as appropriate, the function may also be at least a part of the processor. Processing explained with a function as the subject may be processing performed by a processor or a device including such processor. 
     Moreover, a program may be installed from a program source. A program source may be, for example, a recording medium (for example, non-temporary recording medium) readable with a program distribution computer or a computer. The explanation of each function is an example, and a plurality of functions may be consolidated into one function, or one function may be divided into a plurality of functions. 
     Moreover, as information for identifying elements, arbitrary information (for example, at least one among “ID”, “name”, and “number”) may be adopted. 
     Moreover, in the following explanation, “volume” may be a logical storage space (address space). A volume may be a substantive volume (volume based on a physical storage device (for example, persistent storage device)), or a virtual volume. 
     Several embodiments of the present invention are now explained with reference to the appended drawings. In the following drawings, “volume” is indicated as “VOL”. Moreover, the migration of a volume means the migration of data stored in a volume. 
     First Embodiment 
       FIG.  1    is a diagram showing an overview of the system migration according to the first embodiment. 
     An environment of a migration source is an on-premises environment  100 . A computer system in the on-premises environment  100  includes a computer  101 , and a first storage system  102  connected to the computer  101 . The computer  101  may be a physical computer, and the first storage system  102  may be a physical storage system (for example, so-called disk array device). The first storage system  102  corresponds to a storage system of a migration source. Of the computer  101  and the first storage system  102 , a plurality of computers  101  may exist. The first storage system  102  may comprise a plurality of volumes. 
     An environment of a migration destination is a cloud environment  106  (typically, a public cloud environment). In the cloud environment  106 , a cloud computing service such as a cloud computer service  107  or a cloud storage service  109  is provided. The cloud computer service  107  may be an instance execution environment, and the cloud storage service  109  is a predetermined default cloud storage service that can be accessed by the cloud computer service  107 . 
     The second storage system  112  corresponds to a storage system of a migration destination. In this embodiment, the second storage system  112  is a cloud storage service provided in the cloud environment  106 . 
     The cloud environment  106  is an environment (for example, cloud platform) provided by a cloud vendor, and the cloud computer service  107  and the cloud storage service  109  may be a cloud computing service provided by the cloud vendor. For example, the cloud computer service  107  may be Amazon EC2 (Amazon Elastic Compute Cloud), and the cloud storage service  109  may be Amazon EBS (Amazon Elastic Block Store) (“Amazon” is a registered trademark). The second storage system  112  may be a cloud storage service developed by a storage vendor. Preferably, the second storage system  112  is superior in reliability or function in comparison to the cloud storage service  109 . 
     The migration of a computer or a volume to the cloud environment  106  in an environment that is different from the cloud environment  106  (for example, the on-premises environment  100  or a cloud environment that is different from the cloud environment  106 ) is performed by a cloud migration tool  190 . In other words, in this embodiment, while the migration target is migrated from the on-premises environment  100  to the cloud environment  106 , the present invention may also be applied to the migration from a different cloud environment to the cloud environment  106 . The cloud migration tool  190  is typically a system (function) provided by a vendor of the cloud environment  106 . 
     An information processing system  105  is constructed. The information processing system  105  is a system which supports the migration of the migration target (for example, computer or volume) from a migration source to a migration destination. The information processing system  105  may also be referred to as a management system. The information processing system  105  may be located outside the on-premises environment  100  and the cloud environment  106  as illustrated in the diagram, or may be located inside the on-premises environment  100  or the cloud environment  106 . While the information processing system  105  is a physical system (for example, computer) in this embodiment, it may also be a logical system provided in the physical storage resource. The information processing system  105  can operate, via a communication medium such as a network or a dedicated line, at least one among a computer  101 , a first storage system  102 , a cloud migration tool  190 , a cloud computer service  107 , a computer instance  108 , a cloud storage service  109  and a second storage system  112 . The information processing system  105  may also operate the cloud storage service  109  based on instructions to the second storage system (or without going through another system such as the second storage system  112 ). 
     The information processing system  105  includes an interface device  51 , a storage device  52 , and a processor  53  connected thereto. 
     The interface device  51  is connected, for example, to the foregoing communication medium (for example, network). 
     The storage device  52  stores programs and information. As such information, for example, there is management information  140 . The management information  140  is information that is referenced or updated as needed for the system migration processing (see  FIG.  5   ) to be performed by the information processing system  105 . The management information  140  may include information representing the progress of the system migration processing; for example, the management information  140  may include the information of (a) to (c) below. 
     (a) Computer migration management information as information related to a computer to be migrated from the on-premises environment  100  to the cloud environment  106 . The computer migration management information includes, for example, identifying information of the computer for each computer to be migrated, and information representing the migration status of the computer (for example, migration not yet started, migration start or migration complete).
 
(b) Volume migration management information as information related to a volume to be migrated from the on-premises environment  100  to the cloud environment  106 . The volume migration management information includes, for example, identifying information of the volume for each volume to be migrated, and information representing the migration status of the volume (for example, migration not yet started, migration start or migration complete).
 
(c) Intermediate volume management information as information related to an intermediate volume  111  described later in the cloud storage service  109 . The intermediate volume management information includes, for example, identifying information of the intermediate volume  111  for each intermediate volume  111 , information representing the migration status of the intermediate volume  111  (for example, creation standby, creation complete, migration start, migration complete, deletion start or deletion complete), identifying information of the mapping volume  113  as a volume in which the intermediate volume  111  is virtualized, and identifying information of the target volume  114  as a migration destination of the mapping volume  113 .
 
     As a result of the processor  53  executing programs, functions such as the tool operating unit  151 , the migration completion confirmation unit  152  and the migration control unit  153  are realized. 
     While the first storage system  102  provides a volume to the computer  101 , as the volume recognized by the computer  101 , there are a system volume  103  and a data volume  104 . In other words, a path which connects the computer  101  and the system volume  103  and a path which connects the computer  101  and the data volume  104  are provided (see the dashed line arrow extending from the computer  101 ). The system volume  103  is a volume storing an image of an OS (Operating System) of the computer  101 , and is typically a volume for activating the computer  101 . The data volume  104  is a volume storing data that is input/output by the activated computer  101  (for example, application executed by the computer  101 ). 
     The cloud migration tool  190  is a system (function) which migrates the computer  101  as the computer instance  108  to the cloud computer service  107 , and migrates the system volume  103  of the computer  101  to the cloud storage service  109 . 
     In this embodiment, the system migration processing of migrating a computer and a volume from the on-premises environment  100  to the cloud environment  106  is performed based on the following flow. 
     The tool operating unit  151  issues a migration instruction to the cloud migration tool  190  which designates the computer  101  to be migrated, and the data volume  104  recognized by the computer  101  (S 11 ). For example, the identifying information of the computer  101  and the identifying information of the data volume  104  (for example, volume identifying information recognized by the computer  101 ) are designated. The system volume  103  recognized by the computer  101  may be designated in the cloud migration tool  190  as the migration target as with the data volume  104 , or, if the computer  101  is designated, it may be deemed to have been designated as the migration target without the designation of the system volume  103 . In either case, in this example, the computer  101 , the system volume  103  and the data volume  104  illustrated in the diagrams are the migration targets. Note that the designation of the data volume  104  to be migrated in S 11  may be performed with a separate means such as deleting (detaching) the data volume  104  to be migrated from the computer  101  before the migration instruction is issued to the cloud migration tool  190 . 
     In response to the migration instruction, the cloud migration tool  190  performs the cloud migration processing including the migration of the computer  101 , the system volume  103  and the data volume  104 . Specifically, the cloud migration tool  190  migrates the designated computer  101  as the computer instance  108  to the cloud computer service  107 . Moreover, the cloud migration tool  190  migrates the system volume  103  as the system volume  110  to the cloud storage service  109  (specifically, for example, migration from the volume  103  to the volume  110 ). Moreover, the cloud migration tool  190  migrates the data volume  104  as the intermediate volume  111  to the cloud storage service  109  (specifically, for example, migration from the volume  104  to the volume  111 ). The intermediate volume  111  is a volume that was migrated to the cloud storage service  109  of the data volume  104 . 
     The migration completion confirmation unit  152  confirms that the foregoing cloud migration processing was completed by the cloud migration tool  190  in response to the migration instruction. When the cloud migration processing is completed, the computer instance  108  can access the system volume  110  (see the dashed line arrow extending from the computer instance  108  to the system volume  110 ). The computer instance  108  refers to the system volume  110  and is activated (for example, reads the image of the OS). 
     After the completion of the cloud migration processing is confirmed by the migration completion confirmation unit  152 , the migration control unit  153  creates, in the second storage system  112 , the mapping volume  113  as the volume in which the intermediate volume  111  is virtualized, and migrates data to the target volume  114  from the mapping volume  113  in an online status which enables the I/O of data to and from the computer instance  108 . One volume may concurrently serve as the mapping volume  113  and the target volume  114 . 
     Specifically, for example, the migration control unit  153  causes the second storage system  112  to execute an external connection which associates the intermediate volume  111  with the second storage system  112  (S 12 ). The intermediate volume  111  is thereby recognized by the second storage system  112 . 
     The migration control unit  153  thereafter creates, in the second storage system  112 , the mapping volume  113  as the volume in which the externally connected intermediate volume  111  is virtualized (volume to which the intermediate volume  111  was mapped). When the mapping volume  113  is created, the migration control unit  153  causes the mapping volume  113  to become an online status which enables the I/O of data to and from the computer instance  108 . Specifically, for example, the migration control unit  153  causes the second storage system  112  to provide the mapping volume  113  to the computer instance  108  (for example, causes the computer instance  108  to recognize the mapping volume  113 ), and starts the process of the second storage system  112  receiving the I/O request designating the mapping volume  113 . The migration control unit  153  may permit the computer instance  108  to issue an I/O request to the mapping volume  113 , and the computer instance  108  that received the permission may send, to the second storage system  112 , the I/O request designating the mapping volume  113  as needed according to the processing of the computer instance  108 . 
     The migration control unit  153  causes the second storage system  112  to migrate data from the mapping volume  113  to the target volume  114  (S 13 ). Data is thereby migrated from the mapping volume  113  (specifically, intermediate volume  111  mapped to the mapping volume  113 ) to the target volume  114 . When this data migration is completed, the I/O of data to and from the target volume  114  of the computer instance  108  is thereby enabled (see the dashed line arrow extending from the computer instance  108  to the target volume  114 ). 
     According to the system migration processing described above, the migration of data from the source volume (data volume)  104  of the first storage system  102  to the target volume  114  of the second storage system  112  is realized without a remote copy function of copying data from the first storage system  102  to the second storage system  112  (for example, function of performing remote copy in volume (volume recognized by the storage system) units between storage systems). Thus, even if the first storage system  102  has no compatibility with the second storage system  112 , the data volume  104  in the first storage system  102  can be migrated to the second storage system  112  as a cloud storage service with superior reliability or function in comparison to the default cloud storage service  109 . Note that the second storage system  112  may also exist in an environment that is different from the cloud environment  106  (for example, different cloud environment). 
     Note that, according to the example shown in  FIG.  1   , while the volume to be migrated to the second storage system  112  is the data volume  104 , the system volume  103  may also be migrated to the second storage system  112 . In other words, the system volume  110  is migrated as an intermediate volume, a mapping volume in which the intermediate volume is virtualized is created in the second storage system  112 , and data is migrated from the mapping volume to the target volume, as a result, the target volume may become a system volume that was migrated to the second storage system  112 . 
     Moreover, when there are a plurality of data volumes  104  as the data volumes recognized by the computer  101 , all or a part of the data volumes  104  among the plurality of data volumes  104  may also be migrated to the second storage system  112 . 
     The foregoing explanation related to the system migration processing is now supplemented with reference to  FIG.  2    to  FIG.  4   . 
       FIG.  2    is a diagram showing the configuration of the cloud environment  106  after completion of the cloud migration processing. 
     When the cloud migration processing performed by the cloud migration tool  190  is completed, the intermediate volume  111  is connected to the computer instance  108  in addition to the system volume  110 . In other words, a path which connects the computer instance  108  and the intermediate volume  111  is provided (see the dashed line arrow extending from the computer instance  108  to the intermediate volume  111 ). Here, the I/O of data by the computer instance  108  to and from the intermediate volume  111  may also be started. 
     Nevertheless, in this embodiment, the migration control unit  153  is set so that the I/O of data by the computer instance  108  to and from the intermediate volume  111  is not started. Specifically, for example, the migration control unit  153  may perform at least one of the following. 
     Not permitting the computer instance  108  to issue an I/O request designating the intermediate volume  111  (for example, prohibiting the computer instance  108  from issuing an I/O request designating the intermediate volume  111 ).
 
Not allowing the cloud storage service  109  to start receiving an I/O request designating the intermediate volume  111  (for example, prohibiting the cloud storage service  109  from receiving an I/O request designating the intermediate volume  111 ).
 
       FIG.  3    is a diagram showing the configuration of the cloud environment  106  after creation of the mapping volume  113 . 
     The intermediate volume  111  is externally connected to the second storage system  112 . The external connection method depends on the cloud storage service  109  which includes the intermediate volume  111 . A specific example of the external connection method will be described later. 
     The mapping volume  113 , a volume in which the intermediate volume  111  externally connected to the second storage system  112  is virtualized, is created in the second storage system  112 . The I/O of data from the computer instance  108  to and from the created mapping volume  113  is started. For example, a path which connects the computer instance  108  and the mapping volume  113  is provided in response to an instruction from the migration control unit  153  to the second storage system  112 . An I/O request is issued from the computer instance  108  via the path, and the I/O of data to and from the mapping volume  113  is performed by the second storage system  112  in response to the I/O request. 
     In cases where a path which connects the computer instance  108  and the intermediate volume  111  is provided, the migration control unit  153  may also instruct the cloud storage service  109  (and/or computer instance  108 ) to delete the path (for example, off-lining, or deleting the path setting itself) before a path which connects the computer instance  108  and the mapping volume  113  is provided. The path may also be deleted in response to the instruction. In cases where the computer instance  108 , the cloud storage service  109  and the second storage system  112  are equipped with a multipath function, there may be a time when the path which connects the computer instance  108  and the intermediate volume  111  and the path which connects the computer instance  108  and the mapping volume  113  coexist. 
       FIG.  4    is a diagram showing the migration of data from the mapping volume  113  to the target volume  114 . 
     During the migration of data from the mapping volume  113  to the target volume  114 , the I/O of data to and from the mapping volume  113  (and target volume  114 ) (reception and processing of an I/O request designating the identifying information of the mapping volume  113 ) is possible. Specifically, for example, when the second storage system  112  receives an I/O request designating the identifying information of the mapping volume  113 , the following may be performed. 
     The second storage system  112  determines whether the volume area (area in the volume) of the I/O destination is an area in which the migration of data has been completed.
 
When the result of the determination is false, the second storage system  112  performs the I/O of data to and from the mapping volume  113  (in other words, I/O of data to and from the intermediate volume  111 ).
 
When the result of the determination is true, the second storage system  112  performs the I/O of data to and from the target volume  114 .
 
     In other words, the mapping volume  113  and the target volume  114  may be recognized as one volume, without differentiation, by the computer instance  108 . When the second storage system  112  receives an I/O request designating the one volume, depending on whether the volume area (for example, LBA (Logical Block Address)) designated in the I/O request is a migrated area, the second storage system  112  may perform the I/O of data to and from the mapping volume  113  or the target volume  114  according to the I/O request. 
     Moreover, in the cloud migration processing, the identifying information of the data volume (source volume)  104 , which is also the identifying information recognized by the computer  101 , may be succeeded by the intermediate volume  111 . The foregoing identifying information may also be succeeded by the mapping volume  113  in which the intermediate volume  111  is virtualized. The identifying information succeed by the mapping volume  113  (identifying information of the data volume (source volume)  104 ) may also be recognized by the computer instance  108 . While data is being migrated from the mapping volume  113  to the target volume  114 , the second storage system  112  may receive the I/O request designating the identifying information from the computer instance  108 . After the migration of data from the mapping volume  113  to the target volume  114  is completed, the identifying information (identifying information of the data volume (source volume)  104 ) may be succeeded by the target volume  114 . Based on this kind of succession of the identifying information, the computer instance  108  can, after the migration of the computer  101 , access the target volume  114  by using the identifying information that is the same as the identifying information of the data volume (source volume)  104 . 
     The system migration processing according to this embodiment is now explained. 
       FIG.  5    is a diagram showing a flow of the system migration processing. 
     The migration processing is performed for each migration target (computer and volume) in a migration source environment (on-premises environment  100  in this embodiment) (S 501 ). When all migration targets are migrated from the migration source environment, deletion of the migration source environment may also be performed (S 502 ). 
     In the system migration processing, when there are a plurality of data volumes  104 , migration of the plurality of data volumes  104  may also be performed in parallel. In other words, each time that the completion of migration of each data volume  104  to the cloud storage service  109  is confirmed, external connection to the second storage system  112  of the intermediate volume  111  corresponding to the data volume  104 , creation of the mapping volume  113  in which the intermediate volume  111  is virtualized, and migration of data from the mapping volume  113  to the target volume  114  in a state where the mapping volume  113  is offline, may be performed. In other words, completion of the cloud migration processing may also be confirmed for each data volume  104 . The reduction of time required for the system migration processing can thereby be expected. 
       FIG.  6    is a diagram showing a flow of the migration processing (S 501  of  FIG.  5   ). 
     The start processing of the cloud migration processing (S 600 ) is performed. Specifically, as shown in  FIG.  7   , the tool operating unit  151  receives the designation of the computer  101  and the volume to be migrated from a user (for example, operator of the information processing system  105 ), and then starts the cloud migration processing. Specifically, the tool operating unit  151  issues to a migration instruction to the cloud migration tool  190  designating the designated computer  101  and the designated volume. In response to the migration instruction, the cloud migration tool  190  starts the migration of the designated computer  101  as the computer instance  108  to the cloud computer service  107  (S 700 ), and starts the migration of the designated volume to the cloud storage service  109  (S 701 ). In this embodiment, all or a part of the data volumes  104  among one or more data volumes  104  recognized by the designated computer  101  is designated. Migration to the cloud storage service  109  of the system volume  103  may be performed in S 700 , or performed in S 701 . In S 701  (migration of the volume), the designated data volume  104 , and the system volume  103  recognized by the computer  101  to be migrated, are migrated. In S 701 , the volume in the first storage system  102  is the migration source, and the volume in the cloud storage service  109  may be the migration destination. For example, the intermediate volume  111  is prepared in the cloud storage service  109  for each designated data volume  104 , and the migration of data from the data volume  104  to the intermediate volume  111  is started. S 700  and S 701  may also be performed in parallel. Moreover, the tool operating unit  151  may add the information of the designated computer  101  to the foregoing computer migration management information in the management information  140  (migration status of the computer  101  is “migration start”). Moreover, the tool operating unit  151  may add the information of the volume to be migrated to the foregoing volume migration management information in the management information  140  (migration status of the volume is “migration start”). Moreover, the tool operating unit  151  may add the information of the intermediate volume  111  of the migration destination to the foregoing intermediate volume management information in the management information  140  (migration status of the intermediate volume is “creation standby”). 
     Thereafter, as shown in  FIG.  6   , the completion confirmation processing of the cloud migration processing (S 601 ) is performed. Specifically, as shown in  FIG.  8   , the migration completion confirmation unit  152  confirms the completion of migration of the computer  101  to be migrated (that the computer  101  has been migrated as the computer instance  108  to the cloud computer service  107 ) (S 800 ), and additionally confirms the completion of migration of the designated volume (that the volume has been migrated to the cloud storage service  109 ) (S 801 ) by communicating with the cloud migration tool  190 . S 800  and S 801  may also be performed in parallel. The migration completion confirmation unit  152  may update the management information  140  (for example, migration status of the computer  101  may be updated to “migration complete”, migration status of the volume may be updated to “migration complete”, and migration status of the intermediate volume  111  may be updated to “creation complete”, respectively). 
     After the completion of the cloud migration processing is confirmed, the migration control unit  153  may cause the intermediate volume  111  to become an online status (S 602 ). Specifically, for example, depending on the cloud migration tool  190 , a path for connecting the created intermediate volume  111  and the computer instance  108  may be provided, and the migration control unit  153  may cause this path to be an online status. Nevertheless, S 602  is an option, and S 602  is not performed in this embodiment. 
     After the completion of the cloud migration processing is confirmed, the migration control unit  153  performs the decision processing of the external connection method (S 603 ). For example, as shown in  FIG.  9   , the migration control unit  153  determines a placement location of the intermediate volume  111  (S 900 ), and decides the external connection method according to the determined location. The management information  140  may include external connection management information (information including the identifying information of the location for each location where the intermediate volume  111  is placed (for example, cloud storage service) and the information representing the external connection method), and the migration control unit  153  may perform S 900  by referring to the external connection management information. 
     According to the example shown in  FIG.  9   , when the placement location is cloud storage service A, the migration control unit  153  uses the function equipped in cloud storage service A and decides the external connection method for directly attaching the intermediate volume  111  to a prescribed instance in the second storage system  112  (S 901 ). When the placement location is cloud storage service B, the migration control unit  153  decides an iSCSI connection as the external connection method to the second storage system  112  of the intermediate volume  111  (S 902 ). When the placement location is cloud storage service C, the migration control unit  153  uses the function equipped in cloud storage service C and decides the external connection method for directly attaching the intermediate volume  111  to a prescribed instance in the second storage system  112  (S 903 ). While an external connection to the second storage system  112  of the intermediate volume  111  is required for the virtualization of the intermediate volume  111  (creation of the mapping volume  113 ), since the external connection depends on the placement location of the intermediate volume  111 , the intermediate volume  111  can be externally connected to the second storage system  112  according to a proper external connection method based on the processing shown in  FIG.  9   . 
     As shown in  FIG.  6   , the migration control unit  153  causes the second storage system  112  to execute the external connection according to the external connection method decided in S 603  (S 604 ). The second storage system  112  can thereby externally connect the intermediate volume  111  to the second storage system  112 . 
     Next, the migration control unit  153  causes the second storage system  112  to execute the virtualization of the externally connected intermediate volume  111  (S 605 ). The second storage system  112  can thereby create the mapping volume  113 , a volume in which the intermediate volume  111  is virtualized, in the second storage system  112 . 
     Next, the path switching processing is performed (S 606 ). Specifically, as shown in  FIG.  10   , the migration control unit  153  determines whether the computer instance  108 , the cloud storage service  109  and the second storage system  112  all have a multipath function (S 1000 ). For example, the management information  140  may include information representing whether the computer instance  108 , the cloud storage service  109  and the second storage system  112  respectively have a multipath function, and the determination of S 1000  may be performed based on the management information  140 . Moreover, a “multipath function” is a function in which a plurality of paths is permitted regarding one piece of volume identifying information (for example, each of the plurality of paths is a path in an online status) and one path among such plurality of paths is selected and used. A “path in an online status” is a path that can be used for sending an I/O request. 
     When the result of the determination of S 1000  is true (S 1000 : YES), since a multipath is permitted, the migration control unit  153  adds a path which connects the computer instance  108  and the mapping volume  113  (for example, issues an instruction for adding the path to at least either the computer instance  108  or the second storage system  112 ) (S 1001 ). A path which connects the computer instance  108  and the mapping volume  113  is thereby added. Thereafter, the migration control unit  153  deletes a path which connects the computer instance  108  and the intermediate volume  111  (for example, issues an instruction for deleting the path to at least either the computer instance  108  or the second storage system  112 ) (S 1002 ). A path which connects the computer instance  108  and the intermediate volume  111  is thereby deleted. When the I/O of data has been started via a path which connects the computer instance  108  and the intermediate volume  111  before the path switching processing, the I/O of data can be performed via either the foregoing path, or the path added in S 1001 . In cases where the I/O of data has not been started via a path which connects the computer instance  108  and the intermediate volume  111  before the path switching processing, when a path is added in S 1001 , the migration control unit  153  may instruct the computer instance  108  and the second storage system  112  to start the I/O of data via the added path. When a path which connects the computer instance  108  and the intermediate volume  111  has not been provided before the path switching processing, S 1002  is skipped. 
     When the result of the determination of S 1000  is false (S 1000 : NO), since a multipath is not permitted, the migration control unit  153  deletes a path which connects the computer instance  108  and the intermediate volume  111  (S 1003 ). Thereafter, the migration control unit  153  adds a path which connects the computer instance  108  and the mapping volume  113 , and causes the path to become an online status (S 1004 ). A path which connects the computer instance  108  and the mapping volume  113  is thereby added, and the I/O of data is started via the added path. Note that, in cases where a path which connects the computer instance  108  and the intermediate volume  111  has not been provided before the path switching processing, S 1003  is skipped. 
     As described above, proper path addition and proper path deletion are enabled according to whether or not a multipath has been permitted. 
     Moreover, when a multipath has not been permitted, S 1003  is required before S 1004 . Thus, when the I/O of data is started via a path to and from the intermediate volume  111 , the processing of stopping such I/O is required. In this embodiment, since the I/O of data to and from the intermediate volume  111  is not started, the processing of stopping the I/O is not required. 
     Note that, when it is known in advance that a multipath has been permitted (for example, among S 1000  to S 1004 , S 1000 , S 1003  and S 1004  are constantly not required), the I/O of data may be started via a path to the intermediate volume  111  before the mapping volume  113  is created. This is because the processing of stopping the I/O is not required. 
     After the path switching processing (S 606 ), as shown in  FIG.  6   , the migration control unit  153  causes the second storage system  112  to start the migration of data from the mapping volume  113  to the target volume  114  (S 607 ). The second storage system  112  thereby starts the migration of data from the mapping volume  113  to the target volume  114 . Note that the target volume  114  may be a volume created in the second storage system  112  in response to an instruction from the migration control unit  153 , or a volume designated by the migration control unit  153  among a plurality of volumes in the second storage system  112 . Moreover, as described above, when the second storage system  112  receives an I/O request from the computer instance  108  during the foregoing migration, the I/O of data is performed to and from the mapping volume  113  or the data volume  104  according to the I/O request. The I/O of data to and from the mapping volume  113  is actually performed to the intermediate volume  111 . Moreover, in S 607 , the migration control unit  153  may also update the management information  140  (for example, migration status of the intermediate volume  111  may be “migration start”). 
     The migration control unit  153  confirms the completion of the migration of data from the mapping volume  113  to the data volume  104  (S 608 ). For example, the migration control unit  153  receives a migration complete notice from the second storage system  112 . In S 608 , the migration control unit  153  may also update the management information  140  (for example, migration status of the intermediate volume  111  may be “migration complete”). 
     The migration control unit  153  causes the second storage system  112  to execute the disconnecting of the external connection based on the external connection method decided in S 603  (S 610 ). The second storage system  112  thereby disconnects the external connection to the second storage system  112  of the intermediate volume  111 . 
     The migration control unit  153  causes the cloud storage service  109  to execute the deletion of the intermediate volume  111  in which the migration of data has been completed (S 611 ). The cloud storage service  109  thereby deletes the intermediate volume  111 . It is thereby possible to avoid the wasteful consumption of resources of the cloud storage service  109 . In S 611 , the migration control unit  153  may also update the management information  140  (for example, migration status of the intermediate volume  111  may be “deletion start or deletion complete”). 
     The migration control unit  153  may also cause the first storage system  102  to execute the deletion of the data volume (source volume)  104  (S 612 ). 
     Moreover, in cases where the second storage system  112  comprises a processing logic of executing at least a part of the series of processes (for example, external connection of the intermediate volume  111 , creation of the mapping volume  113 , and migration of data from the mapping volume  113  to the target volume  114 ) after confirming the completion of the cloud migration processing, and the migration control unit  153  issues an instruction designating the necessary parameters (for example, identifying information of the intermediate volume, identifying information of the target volume  114 ) to the processing logic, at least a part of the series of processes described above may be automatically performed. 
     Second Embodiment 
     The second embodiment is now explained. In the following explanation, differences in comparison to the first embodiment will be mainly explained, and the explanation of points that are common with the first embodiment will be omitted or simplified. Note that this point is also the same in the third and fourth embodiments described below. 
       FIG.  11    is a diagram showing an overview of the system migration according to the second embodiment. 
     In the on-premises environment  100 , a hypervisor  120 , a system in which a computer is virtualized, is executed in a physical system (for example, physical computer). The hypervisor  120  executes a computer VM (virtual machine)  121  as a virtualized computer. 
     As volumes provided by the first storage system  102 , for example, there are volumes  811  and  814 . 
     In the volume  811 , a data store  123  for the hypervisor  120  (for example, file system space that can be interpreted by the hypervisor) is created, for example, by the hypervisor  120 . The data store  123  stores a system VM volume  124 , which is a system volume recognized by the computer VM  121 . 
     A data store  125  for the hypervisor  120  is also created in the volume  814 . A data VM volume  127  as a data volume recognized by the computer VM  121  is stored in the data store  125 . A plurality of data VM volumes  127  may exist in one data store  125 . The I/O of data from the computer VM  121  to the data VM volume  127  is performed via the hypervisor  120  and, therefore, data exists in the data VM volume  127  based on a data placement that can be interpreted by the hypervisor  120 . A “VM volume” is a virtual disk as a block device viewed from the computer VM  121 . A “data store” is a storage area of the VM volume. 
     As described above, when a computer is the computer VM  121 , while the I/O of data is performed to the VM volume (VM volume in the data store) via the hypervisor  120 , the data placement in the VM volume is for the hypervisor  120 . In other words, the placement of the VM volume and the data placement of the VM volume (data in the VM volume) cannot be interpreted without the hypervisor  120 . 
     According to the comparative example, considered may be using the foregoing remote copy function (in other words, without going through the cloud storage service  109 ), and migrating the volume  814  from the first storage system  102  to the second storage system  112 . Nevertheless, when the cloud computer service  107  does not have the same hypervisor  120  as the on-premises environment  100 , there are no means for interpreting the data structure as the data store in the volume migrated to the second storage system  112 , placement of the VM volume, and data placement of the VM volume. Accordingly, the data placement of the VM volume migrated to the second storage system  112  cannot be interpreted by the computer instance  108  in the cloud computer service  107 . In other words, it is not possible to migrate data while maintaining a state in which the computer instance  108  is able to interpret the VM volume. 
     Moreover, according to the comparative example, the remote copy function performs the migration in volume units recognized by the storage system. Thus, when there is a plurality of data VM volumes  127  in the volume  814  provided by the first storage system  102 , all of the plurality of data VM volumes  127  is migrated. In other words, data cannot be migrated in data VM volume units. 
     In this embodiment, the data VM volume (and system VM volume) is migrated to the cloud storage service  109  by the cloud migration tool  190 . The cloud migration tool  190  converts a data placement in the VM volume into a data placement that can be interpreted by the computer instance  108  and migrates the VM volume to the cloud storage service  109 . Thus, the data placement of the system VM volume  128  migrated to the cloud storage service  109  of the system VM volume  124  can be interpreted by the computer instance  108  even without the hypervisor  120 . Similarly, the data placement of the data VM volume  129  migrated to the cloud storage service  109  of the data VM volume  127  can be interpreted by the computer instance  108  even without the hypervisor  120 . This data VM volume  129  is the intermediate volume, is virtualized by the second storage system  112 , and data is migrated from the mapping volume  130  (volume in which the data VM volume  129  is virtualized) to the target volume  114 . Consequently, the data placement of the target volume  114  can be interpreted by the computer instance  108 . 
     Moreover, the volumes migrated by the cloud migration tool  190  are units recognized by the computer VM  121 . Thus, even if a plurality of data VM volumes  127  exists in the volume  814 , data can be migrated to the cloud storage service  109  in VM volume units. In other words, certain data VM volumes  127  among the plurality of data VM volumes  127  in one volume  814  can be migrated to the second storage system  112  via the cloud storage service  109 . To put it differently, the remaining data VM volumes  127  among the plurality of data VM volumes  127  in one volume  814  may be excluded from being migrated. 
     Third Embodiment 
       FIG.  12    is a diagram showing an overview of the system migration according to the third embodiment. Note that, due to limitations of space, illustration of the information processing system  105  is omitted in  FIG.  12   . 
     In the third embodiment, virtualization is performed in a layer that is different from the second embodiment. In other words, while virtualization is performed in the hypervisor  120  in the second embodiment, virtualization is performed in the OS (Operating System) of the computer  101  in the third embodiment. For example, an LVM (Logical Volume Manager) is executed in the computer  101 . An LVM is an example of an element that performs virtualization. A volume in the first storage system  102  recognized by the computer  101  is virtualized based on the LVM function. 
     According to an LVM, as the volumes in the first storage system  102 , there are a physical volume (PV) and a logical volume (LV). 
     The physical volume is all or a part of the storage space provided by the physical storage device. In other words, one or more physical volumes are provided from the physical storage device. According to the example shown in  FIG.  12   , there is a plurality of physical volumes  145 ,  146 ,  147  and  148 . 
     According to the example shown in  FIG.  12   , the volumes  71  and  72  are each a volume as a unit recognized by the storage system. For example, when the volume  71  is being recognized by the computer  101  as “sdb”, the physical volumes  145  and  146  are storage spaces (devices) “sdb1” and “sdb2” obtained by the volume  71  being partitioned. These physical volumes  145  and  146  are used in the LVM. 
     As an aggregate of one or more physical volumes, a volume group (VG) is generated by the LVM. According to the example shown in  FIG.  12   , a volume group  12  is generated from the physical volumes  145  to  148 . 
     A logical volume is all or a part of the storage space as a volume group. In other words, one or more logical volumes are provided from a volume group by the LVM. According to the example shown in  FIG.  12   , logical volumes  143  and  144  are provided from the volume group  12 . 
     While the computer  101  is a physical computer in this embodiment, it may also be the computer VM described above. In other words, the third embodiment may also be combined with the second embodiment. The computer  101  respectively recognizes the logical volumes  143  and  144 . 
     According to the comparative example, when migrating a logical volume, processing such as stopping of the I/O of data to the mount points of the logical volumes  143  and  144  in the first storage system  102 , unmounting of the mount points of the logical volumes  143  and  144  from the first storage system  102 , disablement of the volume group  12 , export of the volume group  12 , migration between storage systems in volume units of the volumes  71  and  72  configuring the exported volume group (migration using the foregoing remote copy function), import of the volume group  12  to the second storage system  112  (configuration of the volume group  12  configured with the migrated volumes  71  and  72 ), enablement of the volume group  12 , mounting of the logical volumes  143  and  144 , and starting of the I/O of data to the logical volumes  143  and  144  is performed. In the foregoing case, the problem is the time required for stopping the I/O of data. 
     Moreover, according to the comparative example, volumes will be migrated in the respective units of the volumes  71  and  72 . In other words, migration cannot be performed in logical volume units. 
     In this embodiment, the volumes migrated by the cloud migration tool  190  are the units recognized by the computer  101 . Thus, even if a plurality of logical volumes is provided from the volume group  12 , migration to the cloud storage service  109  is possible in logical volume units. In other words, certain logical volumes among the plurality of logical volumes provided from one volume group  12  can be migrated to the second storage system  112  via the cloud storage service  109 . To put it differently, the remaining logical volumes among the plurality of logical volumes provided from one volume group  12  may be excluded from being migrated. 
     Moreover, since migration in logical volume units is possible in this embodiment, it is not necessary to stop the I/O of data. 
     According to the example shown in  FIG.  12   , the following migration is performed. 
     The logical volume  143  is migrated as an intermediate volume  1149  to the cloud storage service  109 , a mapping volume  1151 , a volume in which the intermediate volume  1149  is virtualized, is created, and data is migrated from the mapping volume  1151  in an online status to a target volume  1152 .
 
The logical volume  144  is migrated as an intermediate volume  1150  to the cloud storage service  109 , a mapping volume  1153 , a volume in which the intermediate volume  1150  is virtualized, is created, and data is migrated from the mapping volume  1153  in an online status to a target volume  1154 .
 
     Fourth Embodiment 
       FIG.  13    is a diagram showing an overview of the system migration according to the fourth embodiment. 
     In the fourth embodiment, a second storage system  1302  is a storage system in a near cloud environment  160 . A “near cloud environment” is an environment (for example, data center) connected to the cloud environment  106  via a dedicated line (for example, high-speed line) and, therefore, the name of “near cloud” is used in the explanation of this embodiment for the sake of convenience. The present invention can also be applied to this kind of second storage system  1302 . 
     Fifth Embodiment 
       FIG.  14    is a diagram showing an overview of the system migration according to the fifth embodiment. 
     In the fifth embodiment, the data volume  104  of the on-premises environment  100  is migrated to the second storage system  1302  of the near cloud environment  160  without going through an intermediate volume. The timing of starting the I/O of data of the computer instance  108  may also be managed by using the computer migration management information and the volume migration management information described above. 
     In this embodiment, migration from the source volume (data volume)  104  of the first storage system  102  to the target volume  114  of the second storage system  1302  is realized without the remote copy function of copying data from the first storage system  102  to the second storage system  1302 . Thus, even if the first storage system  102  has no compatibility with the second storage system  1302 , the data volume  104  in the first storage system  102  can be migrated to the second storage system  1302  with superior reliability or function in comparison to the default cloud storage service  109 . Moreover, since the data volume  104  of the on-premises environment  100  is migrated to the second storage system  1302  of the near cloud environment  160  without going through an intermediate volume, reduction in the time required for the migration and improvement in the reliability of the migration can be expected. 
     Sixth Embodiment 
       FIG.  15    is a diagram showing an overview of the system migration according to the sixth embodiment. 
     In the sixth embodiment, the data volume  104  of the on-premises environment  100  is migrated to the second storage system  112  of the cloud environment  106  without going through an intermediate volume. The timing of starting the I/O of data of the computer instance  108  may also be managed by using the computer migration management information and the volume migration management information described above. 
     In this embodiment, the same effect as the fifth embodiment can be expected. 
     While several embodiments have been explained above, these embodiments are illustrated for explaining the present invention, and are not intended to limit the scope of the present invention only to these embodiments. For example, two or more arbitrary embodiments among the first embodiment to the sixth embodiment described above may be combined. Moreover, a part or all of the processing based on an instruction of the information processing system  105  may be manually executed without going through an instruction of the information processing system  105 . 
     Moreover, in the foregoing explanation, the volume to be migrated is a logical volume. As a general rule, data stored in a logical volume (data stored in a physical volume) is also transferred, together with the logical volume, between the physical volumes (drives) of the first storage system, the cloud storage service, and the second storage system. During the transfer of data, there are cases where a part of the data temporarily exists in the migration source, and the remaining data exists in the migration destination. Thus, for example, when the I/O request is a read request, data is read from the either the migration source or the migration destination, whichever contains the data to be read. Moreover, for example, when the I/O request is a write request, the data may be written in both the migration source and the migration destination. Data can thereby be accessed even during migration. Moreover, information processing system can be included in a system such as the first storage system  102  and/or the second storage system  112 . 
     Moreover, the foregoing explanation can be summarized, for example, in the following manner. The following summary may include the supplementation of the foregoing explanation and the explanation of modified examples. 
     Constructed is an information processing system  105  including a processor  53  and communicable with a cloud computer, a first storage system  102  and a second storage system  112 . When migrating a computer instance  108  as a computer  101  to the cloud computer and migrating data used by the computer instance  108  from the first storage system  102  to the second storage system  112 , the information processing system  105  performs (A) and (B) below. 
     (A) Causes a migration tool  190  of the cloud computer to migrate, from the first storage system  102  to the cloud computer, a system volume  103  storing an image of an OS (Operating System) for configuring the computer instance to be migrated, and a data volume  104  storing data used by the OS.
 
(B) Creates a mapping volume  113 , which has been mapped to an intermediate volume  111  as the data volume migrated to the cloud computer with the migration tool  190 , in the second storage system  112 , and sets a path of data input/output from the computer instance  108  to the mapping volume  113  in the computer instance  108 .
 
     (A) is performed by a tool operating unit  151 . (B) is performed by a migration control unit  153 . In (B), for example, a path is set by the computer instance  108  based on an instruction issued from the migration control unit  153 . At least one of either (A) or (B) may be performed in response to a manual instruction to the information processing system  105 , or performed automatically without such instruction. 
     The information processing system  105  further comprise a migration completion confirmation unit  152  which confirms that the migration by the migration tool  190  is complete. The migration control unit  153  may cause the second storage system  112  to create the mapping volume  113  after the completion of the migration by the migration tool  190  is confirmed. 
     The migration tool  190  may migrate the data volume  104  to the cloud computer based on a data placement that can be interpreted by the computer instance  108 . The second storage system  112  may map an intermediate volume  111  as a data volume of the data placement that can be interpreted by the computer instance  108  to the mapping volume  113  in the second storage system. Moreover, the migration tool  190  may migrate, to the cloud computer, the data volume  104  by converting it into the data placement that can be interpreted by the computer instance. 
     The migration control unit  153  may migrate data from the mapping volume  113  of the second storage system  112  to a target volume  114  in the second storage system  112 , and set a path in the target volume  114  in substitute for setting a path from the computer instance  108  to the mapping volume  113 . 
     The migration control unit  153  may, after completing the migration of data from the mapping volume  113  to the target volume  114  in the second storage system  112 , delete the intermediate volume  111  from the cloud computer. 
     The computer instance may use a plurality of data volumes in a migration source. The tool operating unit  151  may designate a plurality of data volumes used by the computer instance as data volumes to be migrated (for example, designation made to the migration tool  190 ). Each of the designated data volume may be migrated to the cloud computer, and a mapping volume may thereby be created. 
     The migration control unit  153  may decide an an external connection method among a plurality of external connection methods according to the cloud computer which includes the data volume (intermediate volume  111 ), cause at least one of the cloud computer and the second storage system  112  to execute an external connection which associates the data volume (intermediate volume  111 ) with the second storage system according to the decided external connection method, and cause the second storage system  112  to create, in the second storage system  112 , the mapping volume  113  regarding the data volume (intermediate volume  111 ) of the externally connected cloud computer. 
     The migration control unit  153  may determine whether both the cloud computer and the second storage system  112  are compatible with a multipath function. When a result of the determination is true, the migration control unit  153  may add a path which connects the computer instance  108  and the mapping volume  113 , and thereafter delete the path when there is a path which connects the data volume (intermediate volume  111 ) and the computer instance  108 . When a result of the determination is false, the migration control unit  153  may delete a path which connects the data volume (intermediate volume  111 ) and the computer instance  108 , and thereafter add a path which connects the computer instance  108  and the mapping volume  113 . Note that the migration control unit  153  may cause the path to the mapping volume  113  to be an online status without causing the path to the data volume (intermediate volume  111 ) to be an online status. 
     The computer instance may operate on a virtual computer (for example, computer VM  121 ) generated by a hypervisor  120  executed by a physical computer (for example, computer  101 ) before migration. A data volume recognized by the computer instance may be a volume stored in a virtual disk as a data store  123  created by the hypervisor  120  and a volume recognized by the virtual computer. A data placement in the data volume may be a data placement for the hypervisor  120 . The migration tool  190  may convert a data placement in the data volume into a data placement that can be interpreted by the computer instance and migrate the data volume to the cloud computer. 
     The computer instance may manage one or more logical volumes configuring a volume group  12  in the first storage system  122 . The volume group may be one logical space configured from a plurality of physical volumes of the first storage system  102 . The plurality of physical volumes may each be a logical space. A data volume recognized by the computer instance may be a logical volume recognized by the computer instance. 
     The cloud computer may include a compute function and a storage function, and may provide these functions as a cloud service. The compute function may be a function as the cloud computer service  107 . The storage function may be a function as the cloud storage service  109 . The second storage system  112  may be a storage service in a cloud environment which is separate from a cloud environment of the cloud service. Moreover, the second storage system  112  may be a storage system which is connected to the cloud computer of the cloud service. 
     Note that constructed may be an information processing system comprising, in substitute for or in addition to the information processing system  105 , a cloud computer, a first storage system  102 , and a second storage system  112 . The cloud computer may include a compute function and a storage function. When migrating a computer instance to the cloud computer and migrating data used by the computer instance from the first storage system  102  to the second storage system  112 , a migration tool  190  of the cloud computer may migrate, from the first storage system  102  to a storage function of the cloud computer, a system volume storing an image of an OS (Operating System) for the compute function to operate the computer instance to be migrated, and a data volume storing data used by the OS. The second storage system may create a mapping volume  130 , which has been mapped to the data volume (intermediate volume  111 ) migrated to the cloud computer with the migration tool  190  of the cloud computer, in the second storage system  112 , and set a path of data input/output from the computer instance  108  to the mapping volume  130  in the computer instance  108 .