JP4613598B2 - Disk system - Google Patents

Description

  The present invention relates to a method for booting an OS from an external disk system in a blade system and the system.

  As described in Japanese Patent Laid-Open No. 2002-32153, a blade system is a server unit having a structure in which a large number of server units can be mounted in a server unit mounting housing and can be efficiently cooled. Conventionally, when a diskless server unit (blade) in which no disk is mounted in the system starts the OS from an external disk system connected by Fiber or the like, OS data is stored in the external disk system for each blade. It was.

JP 2002-32153 A

  In the above prior art, although the OS data of the blades are similar, the OS data for the number of blades is required, and the storage capacity of the disk system is largely occupied. Also, when applying a security patch or the like, it is necessary to apply to all the OS data, which requires a lot of trouble for users and administrators.

  An object of the present invention is to provide an external disk system that reduces the disk occupation amount and the trouble of an administrator.

  In order to achieve the above object, the disk system of the present invention to which a plurality of computers (blades) are connected performs the following operation.

  For example, when the OS of the blade 1 is started, in order to store the latest OS data including the changed portion in the blade 1, based on the OS data read request from the blade 1, for each data block having a predetermined data length, The following processes a) to d) are repeated a predetermined number of times.

  a) An OS data read request is received from the blade 1 in units of data blocks.

  b) The OS data difference data unique to the blade 1 is searched from the difference management table corresponding to the blade 1.

  c) If there is difference data in the difference management table, the difference data for the retrieved data block is transferred to the memory of the blade 1.

  d) If there is no difference data in the difference management table, the OS data for the data block is extracted from the OS master data storing the OS data common to each blade and transferred to the memory of the blade 1.

  When the OS data is changed during the operation of the blade 1, the disk system receives a write request for the changed OS data from the blade 1, and is included in the received request, and is a data block in which the changed OS data is stored. Are stored in the difference management table corresponding to the blade 1 together with the data block number (LBA) included in the write request. At this time, if difference data corresponding to the LBA indicated by the write request is already stored in the difference management table, the difference data is updated by a new write request, and if not yet stored, the difference data is added. . Each time the OS data is changed in the blade 1, the above-described writing process is executed.

  According to the present invention, there is only one similar OS data in the data storage of the disk system, and the disk occupation amount of the difference data is small, so that the storage capacity of the external disk system can be saved.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 shows the configuration of a disk system according to an embodiment of the present invention.

  In this embodiment, this is realized by a blade system 114 and a disk system 100 connected to each other by a fiber cable 113. The blade system 114 and the disk system 100 communicate by transmitting / receiving request command data 108 and response command data 109.

The blade system 114 is equipped with a plurality of boards (blades) each having the function of one computer, and an operation corresponding to a predetermined application is performed by a combination of one or a plurality of blades among them. It is possible to change the combination of blades corresponding to the application according to the situation.
The blade system 114 includes blade 1 (112a) and blade 2 (112b), and the disk system 100 includes a master logical disk (hereinafter referred to as LU0) including OS master data which is OS (operating system) data common to the blades. (101)), a differential logical disk (hereinafter referred to as LU1 (102a), LU2 (102b)) including a difference management table 115 for managing OS data (change information for OS master data) unique to each blade, and management information 104 And the disk array controller 103 including the request command data processing 105. Here, LU0, LU1, LU2, etc. are logical unit numbers of the disks.

  The management information 104 and request command data processing 105 are stored in the memory 130 in the disk array controller 103.

  The difference management table 115 stores OS data 117 unique to the blade 1. Similarly, the differential logical disk LU2 (102b) also has a differential management table in which OS data unique to the blade 2 is stored. The management information 104 includes a shared LU mapping table 110 and a system mapping table 111, and the request command data processing procedure 105 includes a read request processing procedure 106 and a write request processing procedure 107.

  In FIG. 1, since there is one OS master data, it is only necessary to adapt to one OS data when applying a security patch, and the labor of the administrator can be reduced. In addition, since the OS master data and the difference data are separated at the time of recovery in the event of a failure caused by the difference data, the recovery time can be reduced by separating the link with the difference data and starting from the OS master data. Can be shortened.

  In this embodiment, two blades 1 and 2 and LU1 and LU2 including difference data are shown, but the number of blades and the number of LUs including difference data may be arbitrary.

  Next, each element of the configuration shown in FIG. 1 will be described in detail.

  FIG. 2 shows request command data 108 transmitted from the blade 1 (112 a) included in the blade system 114 to the disk array controller 103 included in the disk system 100. The request command data 108 includes a command name 200, a target LU 201, a logical block address LBA (Logical Block Address) 202 of data to be requested, data 203, and an issuer system name 204. The command name 200 is designated as either writing or reading, and is referred to when determining whether the request is data reading or writing in the request command data processing 105 shown in FIG. The target LU 201 stores the logical unit (LU) number managed by the disk system 100 and is referred to when determining which LU the request is in the request command data processing 105. The logical block address (LBA) is stored in the LBA 202, and is referred to when determining which address on the disk the request is in the read request process 106 or the write request process 107. The data 203 stores binary data to be written at the time of the write request, and is referred to when writing data to the disk in the write request processing 107. The issuer system name 204 stores data that uniquely determines each blade included in the blade system 114, and is referred to when determining which blade the request is from in the request command processing 105. In the read request process 106 or the write request process 107, data input / output operations are performed in units of logical blocks having a predetermined data length.

  FIG. 3 shows response command data 109 returned from the disk array controller 103 included in the disk system 100 to the blade 1 (112a) included in the blade system 114 in response to the request command data. The response command data 108 includes a command name 300 and data 301. The command name 300 designates either writing completion or reading completion, and is stored when processing is completed in the read request processing 106 or the write request processing 107. In the data 301, the read binary data is stored at the time of a response corresponding to the read request from the blade system 114, and the blade system 114 receives this data.

  FIG. 4 shows a shared LU mapping table 110 that is included in the disk array controller 103 and associates the OS master data LU0 (101) with the system mapping table 111. The shared LU mapping table 110 includes a shared LU number 400 and a system mapping table number 401. The shared LU number 400 stores the LU number of the OS master data LU0 (101) used by multiple blades to start the OS. In the request command data processing 105, the shared LU that matches the target LU of the request command data 108 is stored. Refer to it when specifying the number. The system mapping table number 401 stores the number of the system mapping table 111 corresponding to the shared LU number, and is referred to when specifying the system mapping table 111 corresponding to the shared LU number 400 in the request command data processing 105. In the embodiment, an example in which “0” of the system mapping table number 401 corresponding to the LU number 0 of the OS master data LU0 (101) is shown, but the number of the shared LU number 400 and the system mapping table number 401 to be registered is shown. May be arbitrary, and a plurality of OS master data LU0 (101) can be used. This table is created by the system administrator when the OS master data 101 is created in the disk system 100.

  FIG. 5 shows a system mapping table 111 that is included in the disk array controller 103 and associates the blade 1 and the blade 2 with the corresponding difference data LU 102. The system mapping table 111 includes a system name 500 and a differential LU number 501. Data for uniquely determining each blade included in the blade system 114 is stored in the system name 500, and in the request command data processing 105, a blade that matches the issuer system name 204 of the request command data 108 is specified. Refer to. The difference LU number 501 stores the number of the difference LU used by each blade, and is referred to when specifying the difference data LU (102) corresponding to each blade in the request command data processing 105. In this embodiment, an example is shown in which there are differential LU numbers (501) 1 and 2 corresponding to blade 1 (112a) and blade 2 (112b), respectively, but the number of system names 500 and differential LU numbers 501 is arbitrary. But you can. In the present embodiment, an example in which the system mapping table 0 exists is shown, but there are as many system mapping tables 111 as the number of system mapping table numbers in the shared LU mapping table 110 illustrated in FIG. This table is created by the administrator when creating the difference data 102 for the number of blades in the disk system 100.

  FIG. 6 shows the difference management table 115 that stores the LBA indicating the storage location of data and the data when there is a write request to the OS master data LU0 (101), which is included in the difference LU data (102). Show. The difference management table 115 includes a reference LBA 600 and difference data 601. The reference LBA 600 stores the LBA requested to be written to the OS master data LU0 (101). In the read request process 106 or the write request process 107, the reference LBA 600 matching the LBA of the request command data 108 is specified. Referenced when doing. The difference data 601 stores binary data at the time of a write request to the OS master data LU0 (101). In the read request process 106 or the write request process 107, the difference data 601 corresponding to the reference LBA 600 is referred to when reading or writing. In this embodiment, “200”, “201”, and “202” exist as the reference LBA 600, and “data 1-1”, “data 1-2”, and “data 1-3” exist as the difference data 601. Although an example is shown, the numbers of the reference LBA 600 and the difference data 601 increase or decrease as necessary.

  FIG. 7 shows OS data 117 specific to each blade stored in the difference data 601 of the difference management table 115. The OS data 117 unique to each blade includes device information 700, driver information 701, OS information 702, and application information 703. These data are OS data changed during the OS operation in each blade, and are stored in the difference management table 115 as difference data 601 with the OS master data LU0 (101) in units of LBA. This data alone has no meaning as stored data. In this embodiment, the device information 700, the driver information 701, the OS information 702, and the application information 703 exist. However, other information can be written as OS data unique to each blade.

  FIG. 13 shows a data storage location reference table 122 that is referred to when specifying the data storage location when the blade 1 transmits the request command data 108 to the disk array controller 103. Each blade 112 holds this table 122. The data storage location reference table 122 includes a data name 800, a storage LBA 801, and an LBA size 802. The data name 800 stores the target data name when a read or write request is generated by the blade 1 (112a), and an item that matches the requested data name when the request command data 108 is transmitted. Refer to when searching. The storage LBA 801 stores the LBA of the disk in which each data is stored, and is referred to when specifying the LBA storing the requested data when transmitting the request command data 108. The LBA size 802 stores the size of each data, and is referred to when determining the number of times to transmit the request command data 108 when transmitting the request command data 108. In this embodiment, an example in which “boot loader”, “OS loader”, “OS data”, “write data 1”, and “write data 2” exist as the data name 800 is shown. Other OS data can also be included depending on.

  Next, the entire processing flow will be described in detail.

  FIG. 11 shows processing when the blade 1 (112a) starts up the OS for the first time in FIG. The startup process of the blade 1 shown in FIG. 1 includes four processing blocks: 1) boot loader startup, 2) OS loader startup, 3) OS startup, and 4) OS change.

When the blade 1 (112a) is powered on, the BIOS 121 is activated (S40).
1) Boot loader activation:
Next, in order to read the boot loader 118, the value “0” of the storage LBA 801 and the value “1” of the LBA size 802 corresponding to “boot loader” of the data name 800 in the data storage location reference table 122 are acquired (S41). Next, the command name 200 of the request command data 108 is “read”, the LU number “0” of the OS master data 101 is stored in the target LU 201, the value “0” of the stored LBA 801 acquired in the LBA 202, and “blade” is stored in the issuer system name 204. 1 ″ is stored and transmitted to the disk array controller 103 (S42).

  The disk array controller 103 that has received the request command data 108 executes the request command data processing procedure 105 and reads the boot loader 118 from the OS master data 101 (S43). Next, “read complete” is stored in the command name 300 of the response command data 109, the read data (boot loader 118) is stored in the data 301, and transmitted to the blade 1 (112a) (S44).

  The blade 1 (112a) extracts the boot loader 118 from the response command data 109 and loads it into the memory (S45). Next, the value “1” of the LBA size 802 of the data storage location reference table 122 acquired previously is decremented, and since the result is 0, it is determined that all the boot loaders 118 have been read into the memory of the blade 1, The boot loader is activated (S46).

In this embodiment, an example in which the LBA size 802 of the boot loader 118 is “1” is shown, but the value of the LBA 802 may be arbitrary. In that case, the processing of steps S42 to S45 is repeated until the decremented result becomes zero.
2) OS loader startup:
The boot loader 118 activated by the blade 1 (112a), in order to activate the OS loader 119, the value “1” of the storage LBA 801 corresponding to the “OS loader” of the data name 800 of the data storage location reference table 122, the LBA size The value “1” of 802 is acquired (S47). Next, the command name 200 of the request command data 108 is “read”, the LU number “0” of the OS master data 101 is stored in the target LU 201, the stored LBA 801 value “1” acquired in the LBA 202, and the “blade” is stored in the issuer system name 204. 1 ″ is stored and transmitted to the disk array controller 103 (S48).

  The disk array controller 103 that has received the request command data 108 from the boot loader 118 activated by the blade 1 (112a) executes the request command data processing procedure 105 and reads the OS loader 119 from the OS master data 101 (S49). . Next, “read complete” is stored in the command name 300 of the response command data 109, and the read data (OS loader 119) is stored in the data 301 and transmitted to the blade 1 (112a) (S50).

  The blade 1 (112a) loads the OS loader 119 from the response command data 109 into the memory (S51). Next, the value “1” of the LBA size 802 of the data storage location reference table 122 acquired previously is decremented, and since the result is 0, it is determined that all the OS loaders 119 have been read, and the OS loader 119 is Start (S52).

In this embodiment, an example in which the LBA size 802 of the OS loader 119 is “1” is shown, but the value of the LBA 802 may be arbitrary. In that case, the processing from step S48 to S51 is repeated until the decremented result becomes zero.
3) OS startup:
The OS loader 119 activated by the blade 1 (112a) has a value “2” of the storage LBA 801 corresponding to the “OS data” of the data name 800 of the data storage location reference table 122 and the LBA size 802 in order to activate the OS. Value "600" is acquired (S53). Next, the command name 200 of the request command data 108 is “read”, the LU number “0” of the master OS data 101 is stored in the target LU 201, the value “2” of the stored LBA 801 acquired in the LBA 202, and “blade” is stored in the issuer system name 204. 1 ″ is stored and transmitted to the disk array controller 103 (S54).

  The disk array controller 103 that has received the request command data 108 from the OS loader 119 activated by the blade 1 (112 a) executes the read request processing 106 of the request command data processing 105. In step S32 of the write request process 107 (see FIG. 10 described later), since the OS is activated for the first time in the blade 1, the value L2 stored in the OS master data 101 is stored in the reference LBA 600 of the difference management table 115 “2”. "Does not exist. Therefore, the OS data 120 is read from the OS master data 101 (S55). Next, “reading completed” is stored in the command name 300 of the response command data 109, and the read data is stored in the data 301 and transmitted to the blade 1 (112a) (S56).

The blade 1 (112a) loads the OS data 120 from the response command data 109 into the memory (S57). Next, the previously acquired value “600” of the LBA size 802 is decremented, and since the result is not 0, the value of the LBA 202 of the request command data 108 is decremented, and the processing of steps S54 to S57 is repeated. If the decrement result is 0, it is determined that all the OS data 120 has been read, and the OS is activated (S58).
4) OS change:
When the OS is started on the blade 1, a request to write OS data 117 (OS change data) unique to the blade 1 such as device information 700, driver information 701, OS information 702, and application information 703 unique to the blade is generated. To do. In this embodiment, writing of “write data 1” will be described.

  The OS acquires the value “200” of the storage LBA 801 and the value “20” of the LBA size 802 corresponding to “write data 1” of the data name 800 in the data storage location reference table 122 (S59). Next, “write” is written in the command name of the request command data 108, the LU number “0” of the OS master data 101 is stored in the target LU 201, the value “200” of the stored LBA 801 acquired in the LBA 201, “blade 1” "Are stored and transmitted to the disk array controller 103 (S60).

  The disk array controller 103 that has received the request command data 108 from the blade 1 (112a) has the system mapping table number “0” corresponding to the value “0” of the target LU 201 in the write request process 107 of the request command data process 105. The system obtains the differential LU number “1” whose system name 500 is “Blade 1” and refers to the differential management table 115 of the differential data 102. Since the blade 1 starts up the OS for the first time this time, there is no data in the difference management table 115. Therefore, “200” is newly added to the reference LBA 600, and data 203 is newly added to the difference data 601 (S61). Next, “write complete” is stored in the command name 300 of the response command data 109 and transmitted to the blade 1 (112a) (S62).

  When the blade 1 (112a) receives the response command data 109, the value "20" of the LBA size 802 obtained earlier is decremented. Since the result is not 0, the value of the LBA 202 of the request command data 108 is decremented. Then, the value of the data 203 is rewritten to data corresponding to the LBA 202, and the processing of steps S60 to S62 is repeated. When the decremented result is 0, it is determined that all writing of data (OS change data) has been completed.

  FIG. 12 shows a process flow when the blade 1 (112a) starts the OS after the second time in FIG. Here, the processing other than step S85 is the same as in FIG.

  In step 85, at the time of starting the OS, in the request command data processing 105, if there is difference data corresponding to the LBA, this difference data is read as OS data, and if there is no difference data, OS master data is read as OS data. . That is, when the blade 1 (112a) starts up the OS for the second time or later, first, the presence or absence of difference data corresponding to the LBA is checked. If there is difference data, the difference data is preferentially read and the difference data is stored. Only when there is no OS master data is read. As a result, if the OS data has been changed before the current OS startup, a state in which the original OS master data and the difference data (the OS data changed so far) are mixed in the memory of the blade 1 is configured. The Hereinafter, details of the processing in step 85 will be described.

1) When OS data is changed and differential data corresponding to the LBA exists:
In this embodiment, there are 20 values “200” to “219” written in steps S59 to S62 in FIG. 11 in the reference LBA 600 of the difference management table 115. Therefore, when the value of the LBA 202 is “200” to “219” in the repetition of the processing from step S84 to S87, since the value exists in the difference management table 115, the difference data 601 in the difference management table 115 of the difference data 102 is stored. The corresponding data is read from (S85).

2) When OS data is not changed and there is no difference data corresponding to the LBA:
In the request command data processing 105, the blade 1 (112 a) has started the OS for the second and subsequent times, but the reference LBA 600 in the difference management table 115 has a value “2” (OS master) that matches the LBA of the request command 108. Since the storage LBA value of the data 101 does not exist, the disk array controller 103 that has received the request command data 108 from the blade 1 reads the OS data 120 from the OS master data 101 (S85). Next, “reading completed” is stored in the command name 300 of the response command data 109, and the read data is stored in the data 301 and transmitted to the blade 1 (112a) (S86).

  Next, processing of the request command received from the blade 1 performed by the request command data processing 105 of the disk array controller 103 will be described in detail. Although the process for the blade 1 will be described here, the same process is performed for the other blades.

  When the OS of the blade 1 is started, the LBA of the data storage location reference table 122 in FIG. 13 is stored based on the OS data read request from the blade 1 in order to store the latest OS data including the change in the blade 1. The following processing is repeated for the number of times indicated by the size 802. That is, the following process (read request process 106) is repeated for each data block having a predetermined data length as a unit of LBA.

  a) An OS data read request is received from the blade 1 in units of data blocks.

  b) The OS data difference data unique to the blade 1 is retrieved from the difference management table 115 corresponding to the blade 1.

  c) If there is difference data in the difference management table 115, the difference data for the retrieved data block is transferred to the memory of the blade 1.

  d) If there is no difference data in the difference management table 115, the OS data 120 for the data block is extracted from the OS master data 108 storing the OS data common to each blade and transferred to the memory of the blade 1.

  When the OS data is changed during the operation of the blade 1, the write request processing 107 in the request command data processing 105 of the disk array controller 103 receives the changed OS data write request from the blade 1, and is included in the received request. Then, the data block storing the changed OS data is stored in the difference management table 115 corresponding to the blade 1 together with the data block number (LBA) included in the write request. At this time, if difference data corresponding to the LBA indicated by the write request is already stored in the difference management table 115, the difference data is updated by a new write request, and if not yet stored, the difference data is added. The Each time the OS data is changed in the blade 1, the above-described writing process is executed.

  FIG. 8 shows the processing flow of the request command data processing 105 in detail. The processing from step S10 to step S17 shown in FIG. 8 is repeatedly executed for each LBA by the number of times of the LBA size 802.

  When the request command data 108 is received from the blade 1 (112a) (S10), the value “0” of the target LU 201 of the request command data 108 is acquired. Next, referring to the shared LU number 400 of the shared LU mapping table 110, the system mapping table number corresponding to the value “0” of the shared LU number 400 that matches the previously acquired value “0” of the target LU. The value “0” of 401 is acquired (S11). Next, “blade 1” of the issuer system name 204 of the request command data 108 is acquired, and the value of the differential LU number 501 corresponding to “blade 1” that matches the system name 500 of the system mapping table 0 (111). “1” is acquired (S12). Based on the acquired value “1”, the difference management table 115 of the difference data LU (102) is referred to (S13). Next, the command name 200 of the request command data 108 is acquired, and it is determined whether it is a “read request” or a “write request” (S14).

  If the command name 200 is “read request” as a result of the determination, the read request processing 106 is called (S15). At this time, the request command data 108 is passed as an argument. The processing of the read request processing 106 is shown in FIG.

  As a result of the determination, if the command name 200 is “write request”, the write request processing 107 is called (S16). At this time, the request command data 108 is passed as an argument. The process of the write request process 107 is shown in FIG.

  When the read request process 106 or the write request process 107 is completed, response command data 109 is returned as a return value. This response command data is transmitted to the blade 1 (S17).

  FIG. 9 shows the processing of the read request processing 106 shown in step S15 of FIG.

  It is inquired whether the value “0” of the LBA 202 of the request command data 108 passed as an argument exists in the reference LBA 600 of the difference management table 115 (S21). When the value “0” exists in the reference LBA 600 (S22), it is determined that the LBA data of the designated OS master data 101 has been changed, and the value data 1 of the difference data 601 is acquired (S23). . That is, the presence of the value “0” in the reference LBA 600 indicates that there has been some change in the LBA 0 address of the OS master data before, and this matches the value “0” of the request command data 202. In this case, the difference data is read. When the value “0” does not exist in the reference LBA 600, the data is read from the LBA address 0 of the OS master data. The acquired data 1 is stored in the data 301 of the response command data 109 (S25). Next, “read complete” is stored in the command name 300 of the response command data 109. The created response command data is returned to the request command data processing 105 as a return value.

  If the value “0” does not exist in the LBA 600 in step S22, it is determined that the LBA data of the designated OS master data 101 has not been changed, and the designated LBA data of the OS master data 101 is determined. Is acquired (S24). The acquired data is stored in the data 301 of the response command data 109 (S25). Next, “read complete” is stored in the command name 300 of the response command data 109. The created response command data 109 is returned to the request command data processing 105 as a return value.

  FIG. 10 shows the processing of the write request processing 107 shown in step S16 of FIG.

  An inquiry is made as to whether the value “1” of the LBA 202 of the request command data 108 passed as an argument exists in the reference LBA 600 of the difference management table 115 (S31). When the value “1” exists in the reference LBA 600 (S32), the data 2 of the difference data 601 corresponding to the value “1” of the difference management table 115 is overwritten with the data 1 of the data 203 of the request command data 108 ( S33). That is, in the above description, the case where the LBA 202 of the request command data 108 is 1 is described. When the value of the LBA 202 is “1”, this is a request for the OS master data LBA1. As described in the above description, when the value “1” exists in the reference LBA 600, the difference data is used instead of the OS master data. Therefore, in the case of a write request, the value “reference LBA 600” is used as the difference data. The data corresponding to 1 ”will be overwritten. Next, “write complete” is stored in the command name 300 of the response command data 109 (S35). The created response command data 109 is returned to the request command data processing procedure 105 as a return value.

  In step S32, if the value “1” does not exist in the LBA 600, the value “1” of the LBA 202 of the request command data 108 and the data 1 of the data 203 are compared with the reference LBA 600 and the difference data 601 of the difference management table 115. Is added (S34). Next, “write complete” is stored in the command name 300 of the response command data 109 (S35). The created response command data 109 is returned to the request command data processing 105 as a return value.

  It is also possible to store a program for executing the method of the present embodiment described above in a computer-readable storage medium and read it into a memory for execution.

It is explanatory drawing which showed the whole structure of the implementation method of this invention. Example 1 It is the details of command data transmitted from each blade to the disk system. It is the detail of the command data transmitted to each blade from a disk system. It is a table that stores shared LU numbers and system mapping table numbers. It is a table storing system names and differential LU numbers. It is a table storing reference LBA and difference data. It is a table storing blade-specific OS data. It is a flowchart which shows the flow of a process of a request command data processing procedure. It is a flowchart which shows the flow of a process of a read request processing procedure. It is a flowchart which shows the flow of a process of a write request processing procedure. It is a flowchart which shows the flow of a process in case the blade 1 starts for the first time. It is a flowchart which shows the flow of a process in case the braid | blade 1 starts from the 2nd time. It is a table storing the location of OS master data in which data is stored.

Explanation of symbols

100: Disk system 101: OS master data LU
102: Difference data LU
103: Disk array controller 104: Management information 105: Request command data processing procedure 106: Read request processing procedure 107: Write request processing procedure 108: Request command data 109: Response command data 110: Shared LU mapping table 111: System mapping table 112 : Blade 113: Fiber cable 114: Blade system 115: Difference management table 116: Bus 117: Blade specific OS data 118: Boot loader 119: OS loader 120: OS data 121: BIOS
122: Data storage location reference table

Claims (1)

Each of a plurality of computers is a disk system connected to start one of a plurality of OSs;
The disk system is
A plurality of OS master data logical disks for storing OS data commonly used to start one OS commonly used by each of the plurality of computers among the plurality of OSs;
Each of the plurality of computers storing differential data written to each of the OS master data logical disks corresponding to one OS commonly used by each of the plurality of computers among the plurality of OSs. Multiple supported differential data logical disks,
Wherein the plurality of OS master data logical disk connected plurality of the differential data logical disk, before SL and a request command data processing unit for processing the access request from each of a plurality of computers,
The request command data processing unit
A common LU mapping table storing a logical unit number for specifying each of the plurality of OS master data logical disks, and a plurality of system mapping tables storing a correspondence relationship with the differential data logical disk for each logical unit number. Storing the system mapping table number for identifying the system mapping table corresponding to each of the logical unit numbers in association with the logical unit number, and storing the system mapping table Storing a correspondence relationship between a system name that identifies each of the plurality of computers and a differential logical unit number that identifies the differential data logical disk;
Determining if the issued said access request from the computer is a request for said common the logical unit number LU stored in the mapping table,
When the access request is a request for the logical unit number stored in the common LU mapping table, an OS master data logical disk corresponding to the logical unit number is specified from the plurality of OS master data logical disks. The system mapping table corresponding to the logical unit number is identified from the system mapping table number stored in association with the common LU mapping table, and received from the system name stored in the identified system mapping table. Identify the differential data logical disk corresponding to the computer that issued the access request,
When the received access request is a write request, the write data associated with the write request is written as the differential data to the differential data logical disk, and the write position associated with the write request is used as the differential information as the differential data logical Burn to disc,
When the received access request is a read request, the presence / absence of the difference data corresponding to the read request is determined from the difference information stored in the specified difference data logical disk. The differential data corresponding to the read request is read from the data logical disk and responded to the computer. If the differential data is not present, the OS data corresponding to the read request is read from the specified OS master data logical disk. Respond to the computer,
A disk system characterized by that.

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