I 1111111111111111 11111 111111111111111 1111111111 11111 lllll 111111111111111111
`United States Patent
`[19J
`[11] Patent Number:
`6,119,208
`[45]Date of Patent:
`Sep.12,2000
`
`US006119208A
`
`White et al.
`
`MVS DEVICE BACKUP SYSTEM FOR A
`[54]
`
`DATA PROCESSOR U SING A DATA
`
`STORAGE SUBSYST EM SNAPSHOT COPY
`Primary Examiner-John W. Cabeca
`
`
`CAPABILIT Y
`
`Assistant Examiner-Tuan V. Thai
`
`[75]
`Inventors: Michael Wayne White, Lafayette;
`
`
`
`
`
`
`
`
`Patrick James Tomsula, Arvada, both
`
`[57]
`of Colo.
`
`
`
`0 767 431 Al 4/1997 European Pat. Off ......... G06F 11/14
`
`
`
`Attorney, Agent, or Firm-Duft, Graziano & Forest, P.C.
`
`ABSTRACT
`
`[21]
`Appl. No.: 08/844,480
`
`[22]
`Filed: A pr. 18, 1997
`
`The MYS device backup system functions to enable the data
`
`
`
`
`[73]
`Assignee: Storage Technology Corporation,
`
`
`
`
`
`
`processor to manage the device backup function of a disk
`Louisville, Colo.
`
`
`
`data storage subsystem in a manner that minimizes the
`
`
`expenditure of data processor resources. This is accom­
`
`
`
`plished by the MYS device backup system determining the
`
`
`
`source device volume on the data storage subsystem, the
`
`target device volume on the data storage subsystem and
`[51]
`
`
`Int. Cl.7 ............................. G06F 13/00; G06F 12/00
`
`
`
`identifying the extent of both. The MYS device backup
`[52]
`
`
`
`U.S. Cl. ........................... 711/162; 711/111; 711/112;
`
`
`
`system then transmits data to the data storage subsystem,
`711/161
`
`
`
`
`representative of the assignment of DASD full tracks from
`
`
`Field of Search ..................................... 711/161, 162,
`[58]
`
`
`
`
`
`the source device location on the data storage subsystem as
`
`711/111, 112
`
`
`
`
`well as DASD full tracks from the target (backup) device
`
`
`
`location on the data storage subsystem. The data processor
`
`
`based MYS device backup system then uses ECAM channel
`
`
`
`
`programs to instruct the data storage subsystem to perform
`
`
`
`the device backup operation using snapshot track pointer
`
`
`5,212,784 5/1993 Sparks ..................................... 395/575
`
`
`
`5,255,270 10/1993 Yanai et al. ............................ 371/10.2
`
`
`copy operations. Upon conclusion of the device backup
`
`
`
`5,276,860 1/1994 Fortier et al. ........................... 395/575
`
`
`
`operation by the data storage subsystem, the MYS device
`
`
`5,630,092 5/1997 Carreiro et al. ........................ 395/438
`
`
`
`backup system updates the meta data required to complete
`
`
`
`5,649,152 7/1997 Ohran et al. ............................ 395/441
`the device backup operation.
`FOREIGN PATENT DOCUMENTS
`
`[56]
`
`
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`
`
`0 566 967 A2 10/1993 European Pat. Off ......... G06F 11/14
`
`
`
`
`
`16 Claims, 2 Drawing Sheets
`
`-201
`APPLICATION PROGRAM REQUESTS COPY OF SELECTED DEVICE
`
`
`
`
`
`
`
`
`
`MVS DEVICE COPY SYSTEM DETERMINES LOCATION AND
`
`
`
`
`EXTENT OF SOURCE DEVICE
`
`------202
`
`MVS DEVICE COPY SYSTEM DETERMINES LOCATION AND
`
`
`
`,.------.-.__203
`
`EXTENT OF TARGET DEVICE
`
`MVS DEVICE COPY SYSTEM BUILDS AND TRANSMITS TO DATA
`
`
`
`
`
`
`STORAGE SUBSYSTEM A SET OF ECAM CHANNEL PROGRAMS TO
`-204
`
`
`IDENTIFY SOURCE & TARGET LOCATION AND EXTENT DATA
`
`
`
`
`
`DATA STORAGE SUBSYSTEM RETURNS TOKEN
`
`
`
`---.....__,-205
`
`�---....209
`
`------210
`
`MVS DEVICE COPY SYSTEM GENERATES AND TRANSMITS
`
`
`206
`
`
`TO THE DATA STORAGE SUBSYSTEM AN ECAM CHANNEL
`
`
`
`
`MESSAGE TO ACTIVATE THE DEVICE SNAPSHOT COPY PROCESS
`
`DATA STORAGE SUBSYSTEM RETURNS A COPY
`
`
`
`
`
`
`ACKNOWLEDGMENT MESSAGE WITH A POLLING TOKEN
`
`MVS DEVICE COPY SYSTEM POLLS
`
`
`DATA STORAGE SUBSYSTEM
`
`,-·-..._ 208
`
`
`
`
`
`DATA STORAGE SUBSYSTEM RETURNS STATUS
`
`
`
`
`
`MVS DEVICE COPY SYSTEM UPDATES META DATA
`
`
`
`PROCESS COMPLETES
`
`Page 1 of 8
`
`

`

`U.S. Patent
`U.S. Patent
`
`Sep.12,2000
`Sep. 12, 2000
`
`Sheet 1 of 2
`Sheet 1 of 2
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`6,119,208
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`U.S. Patent
`
`Sep.12,2000
`
`Sheet 2 of 2
`
`6,119,208
`
`FIG. 2
`
`APPLICATION PROGRAM REQUESTS COPY OF SELECTED DEVICE
`
`201
`
`MVS DEVICE COPY SYSTEM DETERMINES LOCATION AND
`EXTENT OF SOURCE DEVICE
`
`v--.____ 202
`
`MVS DEVICE COPY SYSTEM DETERMINES LOCATION AND ~
`203
`EXTENT OF TARGET DEVICE
`
`MVS DEVICE COPY SYSTEM BUILDS AND TRANSMITS TO DATA
`STORAGE SUBSYSTEM A SET OF ECAM CHANNEL PROGRAMS TO ~ 204
`IDENTIFY SOURCE & TARGET LOCATION AND EXTENT DATA
`
`DATA STORAGE SUBSYSTEM RETURNS TOKEN
`
`205
`
`MVS DEVICE COPY SYSTEM GENERA TES AND TRANSMITS ~
`206
`TO THE DATA STORAGE SUBSYSTEM AN ECAM CHANNEL
`MESSAGE TO ACTIVATE THE DEVICE SNAPSHOT COPY PROCESS
`
`DATA STORAGE SUBSYSTEM RETURNS A COPY
`ACKNOWLEDGMENT MESSAGE WITH A POLLING TOKEN
`
`v------ 207
`
`MVS DEVICE COPY SYSTEM POLLS
`DATA STORAGE SUBSYSTEM
`
`208
`~
`
`DATA STORAGE SUBSYSTEM RETURNS STATUS
`
`~ 209
`
`1
`
`MVS DEVICE COPY SYSTEM UPDATES META DATA ~ 210
`
`1•
`
`PROCESS COMPLETES
`
`~ 211
`
`Page 3 of 8
`
`

`

`6,119,208
`
`1
`MVS DEVICE BACKUP SYSTEM FOR A
`DATA PROCESSOR USING A DATA
`STORAGE SUBSYSTEM SNAPSHOT COPY
`CAPABILITY
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`This application is related to copending applications titled
`"System For Providing Write Notification During Data Set
`Copy" and "DASD File Copy System For A Data Processor
`Using A Data Storage Subsystem Snapshot Copy
`Capability", filed on the same date as the present invention,
`Ser. No. 08/843,544 (now U.S. Pat. No. 5,915,264) and Ser.
`No. 08/844,046 (now pending), respectively.
`
`2
`device data requires the expenditure of data processor, data
`channel, data storage subsystem and backup data storage
`device resources. In addition, the concurrent access to the
`device data may be hindered due to device request queuing.
`5 This is necessitated by the requirement that the backup data
`represents a single point-in-time copy of the data for the
`entire source device.
`An alternative to the data processor controlled device
`copy operation described above is the data storage sub-
`10 system snapshot copy operation described in U.S. Pat. No.
`5,410,667. This snapshot copy system creates a duplicate
`device pointer in a virtual track directory in the data storage
`subsystem to reference a device that a data processor has
`requested the data storage subsystem to copy. This enables
`the data processor to access the device via two virtual
`15 addresses while only a single physical copy of the device
`resides in the data storage subsystem. The snapshot copy
`operation is effected without the involvement of the data
`processor, since it is managed solely within the data storage
`subsystem. However, the snapshot copy operation cannot be
`20 selected by the data processor, but is because it is solely
`within the purview of the data storage subsystem. In
`addition, the snapshot copy operation is not available for use
`in creating a backup copy of an MYS device.
`
`SOLUTION
`The above described problems are solved and a technical
`advance achieved in the field by the MYS device backup
`system of the present invention which functions to enable
`the data processor to manage the device backup function in
`30 a manner that minimizes the expenditure of data processor
`resources. This is accomplished by the MYS device backup
`system designating the source and destination device vol(cid:173)
`umes and then activating the snapshot copy resources of the
`data storage subsystem to perform the device backup opera-
`35 tion without the necessity of the data processor being
`involved in the execution details of the operation. In
`addition, the instantaneous creation of a backup copy of the
`device data maintains a point-in-time image of the device
`data from the initiation of the device backup process until a
`40 physical backup copy of the device data is available.
`The implementation of the MYS device backup system is
`data processor based, yet the DASD volume device backup
`is performed without using data processor CPU resources to
`perform the actual movement of the device data. Thus, the
`45 traditional data reads to data processor memory and the
`write channel programs are not utilized to copy the device
`data from a source device location to a target (backup)
`device location. Instead, the MYS device backup system
`determines the source device volume on the data storage
`50 subsystem, the target device volume on the data storage
`subsystem and identifies the extents of both. The MYS
`device backup system then transmits data to the data storage
`subsystem, representative of the assignment of DASD full
`tracks from the source device location on the data storage
`55 subsystem as well as DASD full tracks from the target
`(backup) device location on the data storage subsystem. The
`data processor based MYS device backup system then uses
`Extended Channel Access Method (ECAM) channel pro(cid:173)
`grams to instruct the data storage subsystem to perform the
`60 MYS device backup operation using the data storage sub(cid:173)
`system snapshot track pointer copy operations. Upon con(cid:173)
`clusion of the device backup operation by the data storage
`subsystem, the MYS device backup system updates the meta
`data required to complete the device backup operation. Meta
`65 data is the supporting volume and device structures, stored
`in the data processor, that identify the devices and maintain
`the device status.
`
`FIELD OF THE INVENTION
`This invention relates to data storage subsystems, and, in
`particular, to an MYS device backup system which is
`resident on a data processor and which regulates the backup
`of an MYS device on to the virtual data storage devices of
`a data storage subsystem which is connected to the data
`processor. The MYS device backup system manages the
`designation of the source and target data storage volumes
`and activates the snapshot copy resources of the data storage
`subsystem to perform the device backup operation without 25
`the necessity of the data processor having to expend a
`significant amount of processing resources.
`PROBLEM
`It is a problem in the field of computer systems to
`efficiently create backup copies of the data sets of an MYS
`device, which backup copies represent a single point-in-time
`for all data resident on the source MYS device. In a typical
`computer system, data processors are connected to one or
`more data storage subsystems, which include disk drive
`memory systems. The data processors and their associated
`data storage subsystems therefore must manage the backup
`of data sets stored on the virtual volumes of the data storage
`subsystem in a manner that does not adversely impact the
`performance and efficiency of the data processor and which
`also ensures the integrity of the data.
`The backup of device data in a traditional DASD data
`storage subsystem entails the data processor retrieving the
`device data from the data storage subsystem, then writing
`the retrieved device data to a designated backup data storage
`location in the data storage subsystem. In particular, as part
`of this process, device data backup utilities perform volume
`track level backup by executing a series of read and write
`channel programs. These channel programs read data from
`the data storage subsystem into memory on a data processor
`and then write the data back out to the backup data storage
`subsystem as a series channel programs from that data
`processor memory. This system is resource intensive, in that
`the data processor expends a significant amount of resources
`(CPU cycles) to achieve the device data backup operation.
`In addition, channel resources are needed to perform the data
`processor based device backup operation. Furthermore, two
`significant difficulties with data storage subsystems are the
`time required to make backup copies of device data and the
`need to maintain the consistency of the device data during
`the time it takes to make backup copies of the device data.
`This is a significant issue when a backup copy must be made
`of a large devices which may contain many devices or data
`bases which are the target of a single or common application
`programs.
`Several further problems are encountered in the creation
`of backup copies. The creation of physical backup copies of
`
`Page 4 of 8
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`6,119,208
`
`3
`This MYS device backup system is a significant departure
`from the prior art operation of data storage subsystems since
`it does not require the expenditure of a significant amount of
`the data processor resources. In addition, the existing data
`storage subsystem snapshot copy capability is used to enable
`the data processor to control the copying of device data to
`designated backup data storage locations.
`
`BRIEF DESCRIPTION OF IBE DRAWING
`
`FIG. 1 illustrates in block diagram form the overall
`architecture of a data system which includes the MYS
`device backup system of the present invention; and
`FIG. 2 illustrates in flow diagram form the operational
`steps taken by the MYS device backup system.
`
`DETAILED DESCRIPTION
`
`FIG. 1 illustrates in block diagram form the overall
`architecture of a computer system 1 that incorporates the
`MYS device backup system BS of the present invention. The
`computer system 1 includes at least one data processor 11 to
`which are connected at least one data storage subsystem
`(DSS) 3, 3' that contains at least one and likely a plurality of
`data storage devices DS1-DS4 for reading and writing data
`onto data storage media for use by the data processor 11.
`The data storage subsystem 3, 3' comprises a dynamically
`mapped virtual device data storage subsystem which imple(cid:173)
`ments a plurality of virtual data storage devices. In the
`preferred embodiment of the invention disclosed herein, the
`data storage subsystem 3 comprises a disk drive array data
`storage subsystem, although any data storage technology
`can be used to implement the data storage subsystem 3. For
`the purpose of simplicity of description, the disk drive array
`data storage subsystem example is used herein.
`Mapping Tables
`The data storage subsystem 3 dynamically maps between
`three abstract layers: virtual, logical and physical. The
`virtual layer functions as a conventional large form factor
`disk drive memory. The logical layer functions as an array
`of storage units that are grouped into a plurality of redun(cid:173)
`dancy groups. The physical layer functions as a plurality of
`individual small form factor disk drives. The data storage
`subsystem 3 effectuates the dynamic mapping of data among
`these abstract layers and controls the allocation and man(cid:173)
`agement of the actual space on the physical devices. These
`data storage management functions are performed in a
`manner that renders the operation of the data storage sub(cid:173)
`system 3 transparent to the data processor 11, which per(cid:173)
`ceives only the virtual image of the data storage subsystem
`3. A virtual device is therefore an entity addressable by data
`processor 11, with data processor-controlled content and
`data processor-managed space allocation. In this system, the
`virtual device consists of a mapping of a large form factor
`disk drive image onto a plurality of small form factor disk
`drives which constitute at least one redundancy group within
`the disk drive array. The virtual to physical mapping is
`accomplished by the use of a Virtual Device Table (VDT)
`entry which represents the virtual device. The "realization"
`of the virtual device is the set of Virtual Track Directory
`(VTD) entries, associated with the VDT entry each of which
`VTD entries contains data indicative of the Virtual Track
`Instances, which are the physical storage locations in the
`disk drive array redundancy group that contain the data
`records. The data storage management functions are per(cid:173)
`formed in a manner that renders the operation of the data
`storage subsystems 3, transparent to data processors 11.
`
`4
`Device Snapshot Copy Operation
`As described in U.S. Pat. No. 5,410,667, the data storage
`subsystem 3 includes a device copy capability which is
`termed a "snapshot copy" operation. The device snapshot
`5 copy operation instantaneously creates a second instance of
`a selected device by merely generating a new pointer to
`reference the same physical memory location as the original
`reference pointer in the virtual track directory. In this
`fashion, by simply generating a new pointer referencing the
`10 same physical memory space, the device can be copied. A
`physical copy of the original device can later be written as
`a background process to a second memory location, if so
`desired. Alternatively, when one of the programs that can
`access the device writes data to or modifies the device in any
`15 way, the modified track is written to a new physical memory
`location and the corresponding address pointers are changed
`to reflect the new location of this rewritten portion of the
`device.
`This apparatus therefore instantaneously copies the origi-
`20 nal device without the time penalty of having to copy the
`track to the data processor 11 and then write the track to a
`new physical memory location on the data storage sub(cid:173)
`system 3 via data channel 21. For the purpose of enabling a
`program to simply access the track at a different virtual
`25 address, the use of this mechanism provides a significant
`time advantage. In this fashion, a track can be instanta(cid:173)
`neously copied by simply creating a new memory pointer
`and the actual physical copying of the track can take place
`as a background process without the involvement of the data
`30 processor 11.
`Operation of MYS Device Backup System
`FIG. 2 illustrates in flow diagram form the operation of
`the MYS device 10 backup system BS, as implemented in
`the system environment described above. The MYS device
`35 backup system BS is illustrated herein as a device manage(cid:173)
`ment process using the snapshot track level subsystem copy
`facility which is extant on the data processor 11, although
`other implementations, such as merging the functionality of
`the MYS device backup system BS into the other software
`40 running on data processor 11, are possible. In operation, data
`processor 11 requests the creation of a backup copy of an
`MYS device at step 201, which MYS device comprises a
`plurality of volumes of data sets stored on a virtual device
`on a one (for example DSS 3) of the data storage subsystem
`45 connected to data processor 11. The MYS device backup
`system BS, in response to the receipt of a device backup
`request, which includes an identification of the selected
`(source) MYS device, locates the identified source MYS
`device at step 202 and serializes the device staging request.
`50 The MYS device backup system BS searches the DSCB
`entries of the Volume Table of Content (VTOC) available to
`the data processor 11 and executes device type queries
`where necessary to thereby determine the device character(cid:173)
`istics of the identified source MYS device as designated by
`55 the data processor 11. However, the data storage subsystem
`3 stores data for the data processor 11 in virtual volumes, a
`plurality of which are implemented in data storage sub(cid:173)
`system 3, as for example 256 logical DASD volumes. Thus,
`the device location information obtained by the MYS device
`60 backup system BS comprises the data processor view of the
`data storage location in which the selected source MYS
`device is stored on data storage subsystem 3.
`The MYS device backup system BS, in response to the
`receipt of a device backup request, also locates or allocates
`65 a target location for the storage of the copy of the selected
`source MYS device at step 203. The MYS device backup
`system BS searches the DSCB entries of the VTOC avail-
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`6,119,208
`
`5
`able to the data processor 11 and executes device type
`queries where necessary to thereby determine the physical
`location of available memory space of sufficient extent to
`store the copy of the identified source MYS device. In
`addition, the selection of the online candidate backup device 5
`can be accomplished by user request or automatically
`selected based upon device usage criteria. The MYS device
`backup system BS typically queries the backup device to
`determine relevant information regarding the present state of
`this device, including device label, device characteristics,
`available memory, and the like. Once the backup device has
`been selected, the device is serialized by the MYS device
`backup system BS. The data storage subsystem 3 stores data
`for the data processor 11 in virtual volumes, a plurality of
`which are implemented in data storage subsystem 3 and the
`device location information obtained by the MYS device
`backup system BS comprises the data processor view of the
`data storage location in which the copy of the selected
`device will be stored on data storage subsystem 3, if data
`storage subsystem 3 is the target device for storage of the 20
`backup copy of the identified MYS device.
`Once the source and target locations are identified, the
`MYS device backup system BS, at step 204, builds a set of
`ECAM channel programs to activate the copying of the
`identified source MYS device, and the associated creation of 25
`track pointers. In operation, the MYS device backup system
`BS creates an ECAM channel message for each extent of
`tracks that are to be copied in the identified source MYS
`device. These ECAM messages are submitted serially to the
`data storage subsystem 3 to effect the device backup opera- 30
`tion. In particular, the MYS device backup system BS issues
`an ECAM source definition message to the data storage
`subsystem 3 to define both the Source and Target Locations
`as well as the Extent for both of these locations. The MYS
`device backup system BS transmits the ECAM source
`definition message to the data storage subsystem 3 over the
`data channel 21 which connects these two systems in well
`known fashion. The ECAM source definition message is
`used to prepare the data storage subsystem 3 for the execu(cid:173)
`tion of the device snapshot copy operation and also func- 40
`tions as a security measure. The security aspect of the
`process involves the passing of a token at step 205 from the
`data storage subsystem 3 to the MYS device backup system
`BS to tie the received data with future instructions received
`from the MYS device backup system BS. In response to the 45
`receipt of the ECAM source definition message, the data
`storage subsystem 3 stores the received Source and Target
`Location data as well as the Extent data for future use.
`The MYS device backup system BS at step 206 generates
`an ECAM Target Execution message which instructs the 50
`data storage subsystem 3 to execute the requested MYS
`device backup operation, using the Source and Target
`Location, and Extent data received in the previous ECAM
`source definition message. This message is tied to the
`previously transmitted ECAM source definition message by 55
`the inclusion of the token which was received from the data
`storage subsystem 3 in the previously executed ECAM
`source definition message exchange. The data storage sub(cid:173)
`system 3 uses the token included in the ECAM Target
`Execution message to identify the stored Source and Target 60
`Location and Extent data to perform the MYS device backup
`operation in well known fashion. Since the data storage
`subsystem snapshot copy operation executes independent of
`the data processor, the data storage subsystem 3 returns an
`MYS device backup acknowledgment message, including a 65
`polling token, at step 207 to the MYS device backup system
`BS on data processor 11. This polling token enables the
`
`6
`MYS device backup system BS to query the data storage
`subsystem 3 to ascertain the completion status of the MYS
`device backup process, which physical copy is created as a
`background process, as noted above.
`The MYS device backup query is implemented via the use
`of an ECAM Status Inquiry message, which comprises a
`status inquiry message. The MYS device backup system BS
`inserts the polling token in the ECAM Status Inquiry mes(cid:173)
`sage to identify the particular device snapshot copy opera-
`10 tion of interest (which represents the MYS device backup)
`and transmits the message at step 208. The data storage
`subsystem 3 responds to a received ECAM Status Inquiry
`message by returning a response at step 209 indicative of
`snapshot copy (MYS device backup) completed status. The
`MYS device backup system BS can originate as many
`15 ECAM Status Inquiry messages as needed until the data
`storage subsystem 3 transmits a response to the ECAM
`Status Inquiry message which indicates successful comple(cid:173)
`tion of the device snapshot copy (MYS device backup)
`operation.
`Once the MYS device backup operation is completed, the
`MYS device backup system BS at step 210 must update the
`meta data associated with the Target backup MYS device.
`The meta data comprises: VTOC; Volume labels; VTOC
`index; Virtual Volume Data Set (VVDS) data, which is data
`processor 11. The MYS device backup system BS updates
`this data in well-known fashion to accurately reflect the
`location and extent of both the source MYS device as well
`as the backup copy of the MYS device created by the device
`snapshot copy operation of the data storage subsystem 3.
`Once the MYS device backup system BS updates the meta
`data, the MYS device backup system BS forces device
`recognition processing to be activated for the backup MYS
`device, which thereby allows concurrent access to both the
`source MYS device and the backup MYS device. At this
`35 juncture, the MYS device backup operation is completed
`and processing exits at step 211.
`
`SUMMARY
`The MYS device backup system therefore functions to
`enable the data processor to manage the device backup
`function of a disk data storage subsystem in a manner that
`minimizes the expenditure of data processor resources. This
`is accomplished by the MYS device backup system deter(cid:173)
`mining the source MYS device on the data storage
`subsystem, the target MYS device on the data storage
`subsystem and identifying the extents of both. The MYS
`device backup system then transmits data to the data storage
`subsystem, representative of the assignment of DASD full
`tracks from the source MYS device location on the data
`storage subsystem as well as DASD full tracks from the
`target MYS device location on the data storage subsystem.
`The data processor based MYS device backup system then
`uses ECAM channel programs to instruct the data storage
`subsystem to perform the MYS device backup operation
`using snapshot track pointer copy operations. This elimi(cid:173)
`nates the need for the data processor to be intimately
`involved in the execution of the MYS device backup opera(cid:173)
`tion.
`What is claimed:
`1. A device backup apparatus for the copying of of a
`selected data storage device which is stored on a dynami(cid:173)
`cally mapped virtual memory data storage subsystem having
`a rewriteable memory space, which device backup apparatus
`is extant on a data processor connected to the data storage
`subsystem which is operational to instantaneously create a
`copy of a selected device independent of said data processor,
`said device backup apparatus comprising:
`
`Page 6 of 8
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`6,119,208
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`5
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`10
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`7
`means for allocating memory in said rewriteable memory
`space for a selected device written thereon as well as
`for a copy of said selected device;
`means for transmitting control messages to said data
`storage subsystem to identify all data sets which com-
`prise said selected device, and memory space for said
`copy of said selected device;
`means for activating said data storage subsystem to imple(cid:173)
`ment said instantaneous copy operation on said iden(cid:173)
`tified all said data sets which comprise said selected
`device; and
`means, responsive to said data storage subsystem copying
`said selected device, for updating meta data associated
`with a copy of said selected device created by said data
`storage subsystem, which metadata is known by said
`data processor.
`2. The device backup apparatus of claim 1 wherein said
`means for allocating memory comprises:
`means for determining a location and an extent of said 20
`selected device.
`3. The device backup apparatus of claim 1 wherein said
`means for allocating memory comprises:
`means for determining a location and an extent of said
`copy of said selected device.
`4. The device backup apparatus of claim 1 wherein said
`means for transmitting control messages comprises:
`means for transmitting data to said data storage subsystem
`to identify a location and an extent of said selected
`device, and a location and an extent for said copy of
`said selected device.
`5. A device backup apparatus for the copying of of a
`selected data storage device which is stored on a dynami(cid:173)
`cally mapped virtual memory data storage subsystem having
`a rewriteable memory space, which device backup apparatus 35
`is extant on a data processor connected to the data storage
`subsystem which is operational to instantaneously create a
`copy of a selected device independent of said data processor,
`said device backup apparatus comprising:
`means for allocating memory in said rewriteable memory 40
`space for a selected device written thereon as well as
`for a copy of said selected device;
`means for transmitting control messages to said data
`storage subsystem to identify all data sets which com(cid:173)
`prise said selected device, and memory space for said
`copy of said selected device;
`means for activating said data storage subsystem to imple(cid:173)
`ment said instantaneous copy operation on said iden(cid:173)
`tified all said data sets which comprise said selected
`device; and
`means, responsive to said data storage subsystem copying
`said selected device, for updating meta data associated
`with a copy of said selected device created by said data
`storage subsystem, which metadata is known by said 55
`data processor, comprising:
`means for updating at least one of device meta data
`comprising:
`VTOC; Volume labels; VTOC index; VVDS data.
`6. The device backup apparatus of claim 5 wherein said 60
`means for allocating memory comprises:
`means for determining a location and an extent of said
`selected device.
`7. The device backup apparatus of claim 5 wherein said
`means for allocating memory comprises:
`means for determining a location and an extent of said
`copy of said selected device.
`
`8
`8. The device backup apparatus of claim 5 wherein said
`means for transmitting control messages comprises:
`means for transmitting data to said data storage subsystem
`to identify a location and an extent of said selected
`device, and a location and an extent for said copy of
`said selected device.
`9. A device backup method for the copying of a selected
`data storage device which is stored on a dynamically
`mapped virtual memory data storage subsystem having a
`rewriteable memory space, which device backup method is
`extant on a data processor connected to the data storage
`subsystem which is operational to instantaneously create a
`copy of a selected device independent of said data processor,
`15 said device backup method comprising the steps of:
`allocating memory in said rewriteable memory space for
`a selected device written thereon as well as for a copy
`of said selected device;
`transmitting control messages to said data storage sub(cid:173)
`system to identify said selected device, and memory
`space for said copy of said selected device;
`activating said data storage subsystem to implement said
`instantaneous copy operation on said identified all data
`sets which comprise said selected device; and
`updating, in response to said data storage subsystem
`copying said selected device, meta data associated with
`said device and known by said data processor.
`10. The device backup method of claim 9 wherein said
`30 step of allocating memory comprises:
`determining a location and an extent of said selected
`device.
`11. The device backup method of claim 9 wherein said
`step of allocating memory comprises:
`determining a location and an extent of said copy of said
`selected device.
`12. The device backup method of claim 9 wherein said
`step of transmitting control messages comprises:
`transmitting data to said data storage subsystem to iden(cid:173)
`tify a location and an extent of said selected device, and
`a location and an ext