Apparatus and method to maintain information using a plurality of storage attributes

[0001] Applicant's invention relates to an apparatus and method to maintain information using a plurality of assigned storage attributes. In certain embodiments, those one or more assigned storage attributes are stored in a virtual tape system.

[0002] In hierarchical computer storage systems, intensively used and fast storage are paired with arrays of slower and less frequently accessed data devices. One example of high-speed, expensive memory is a direct access storage device file buffer (DASD). Slower storage devices include tape drives and disk drive arrays, which are less expensive than a DASD.

[0003] One such hierarchical storage system is a virtual tape storage system. Such a virtual tape storage system may include, for example, one or more virtual tape servers (“VTS”) in combination with one or more data storage and retrieval systems, such as the IBM 3494 Media Storage Library. During operation, the virtual tape storage system is writing data from a host to the numerous data storage devices disposed in the one or more data storage and retrieval systems.

[0004] Automated data storage and retrieval systems are known for providing cost effective access to large quantities of stored media. Generally, a data storage and retrieval system includes a large number of storage slots on which are stored portable data storage media. The typical portable data storage media is a tape cartridge, an optical cartridge, a disk cartridge, electronic storage media, and the like. By electronic storage media, Applicants mean a device such as a PROM, EPROM, EEPROM, Flash PROM, and the like.

[0005] One (or more) accessors typically accesses the data storage media from the storage slots and delivers the accessed media to a data storage device for reading and/or writing data on the accessed media. Suitable electronics operate the accessor(s) and operate the data storage device(s) to provide information to, and/or to receive information from, an attached on-line host computer system.

[0006] Applicants' invention includes a method and apparatus to maintain information in a virtual tape system comprising a library inventory using a plurality of storage construct names. Applicants' method includes creating a logical volume comprising information, and assigning (N) storage construct names to that logical volume, where (N) is greater than or equal to 0 and less than or equal to 4. Applicants' method provides the logical volume and the (N) storage construct names to the virtual tape system. Applicants' method assigns four storage management attributes to that logical volume using the (N) storage construct names. Applicants' method then selects storage management actions for the logical volume based upon those four storage management attributes.

[0015] Referring to the illustrations, like numerals correspond to like parts depicted in the figures. The invention will be described as embodied in a virtual tape server in combination with an automated data storage and retrieval subsystem for use in a data processing environment. The following description of Applicant's apparatus and method is not meant, however, to limit Applicant's invention to either data storage and retrieval systems, or to data processing applications, as the invention herein can be applied to data storage in general.

[0016] FIG. 3 illustrates the hardware and software environment in which preferred embodiments of the present invention are implemented. Virtual tape server (VTS) 300 is pictured, operatively coupled to a host computer 390. In certain embodiments, host computer 390 comprises a single computer. In alternative embodiments, host computer 390 comprises one or more mainframe computers, one or more work stations, one or more personal computers, combinations thereof, and the like.

[0017] Host computer 390 communicates with VTS 300 via communication link 392 with a host-to-data interface 380 disposed within the virtual tape server 300. Communication link 392 comprises a serial interconnection, such as an RS-232 cable or an RS-432 cable, an ethernet interconnection, a SCSI interconnection, a Fibre Channel interconnection, an ESCON interconnection, a FICON interconnection, a Local Area Network (LAN), a private Wide Area Network (WAN), a public wide area network, Storage Area Network (SAN), Transmission Control Protocol/Internet Protocol (TCP/IP), the Internet, and combinations thereof. In certain embodiments, the host-to-data interface 380 comprises an IBM Enterprise Systems Connection (ESCON) and communication link 392 comprises a fiber optic local area network used to link mainframes to disk drives or other mainframes.

[0018] VTS 300 also communicates with direct access storage device (DASD) 310, a plurality of data storage devices 130/140 and library manager 160. Data storage devices 130 and 140, and library manager 160, are disposed within one or more data storage and retrieval systems, such as data storage and retrieval systems 100 (FIG. 1)/200 (FIG. 2). In certain embodiments, DASD 310 is integral with host 390. In certain embodiments, DASD 310 is integral with VTS 300. In certain embodiments, DASD 310 is integral with a data storage and retrieval system. In certain embodiments, DASD 310 is external to host 390, VTS 300, and the one or more data storage and retrieval systems in communication with VTS 300. In the embodiment of FIG. 3, library manager 160 communicates with data storage devices 130 and 140. In alternative embodiments, library manager 160 does not directly communicate with data storage devices 130/140.

[0019] VTS 300 further includes storage manager 320, such as the IBM Adstar® Distributed Storage Manager. Storage manager 320 controls the movement of data from DASD 310 to information storage media mounted in data storage devices 130 and 140. In certain embodiments, storage manager 320 includes an ADSM server 322 and an ADSM hierarchical storage manager client 324. Alternatively, server 322 and client 324 could each comprise an ADSM system. Information from DASD 310 is provided to data storage devices 130 and 140 via ADSM server 322 and SCSI adapter 385.

[0020] VTS 300 further includes autonomic controller 350. Autonomic controller 350 controls the operations of DASD 310 through the hierarchical storage manager (HSM) client 324, and the transfer of data between DASD 310 and data storage devices 130 and 140. Library manager 160 communicates with autonomic controller 350.

[0021] From the host computer 390 perspective, device daemons 370, 372, and 374 appear to comprise multiple data storage devices attached to the host-to-data interface 380. Information is communicated between DASD 310 and host 390 via storage manager 320 and one or more of device daemons 370, 372, and 374.

[0022] Host computer 390 comprises a computer system, such as a mainframe, personal computer, workstation, etc., including an operating system such as Windows, AIX, Unix, MVS, LINUX, etc. (Windows is a registered trademark of Microsoft Corporation; AIX is a registered trademark and MVS is a trademark of IBM Corporation; and UNIX is a registered trademark in the United States and other countries licensed exclusively through The Open Group.) In certain embodiments, host computer 390 includes a storage management program 394 (not shown in FIG. 3). The storage management program 394 in the host computer 390 may include the functionality of storage management type programs known in the art that manage the transfer of data to a data storage and retrieval system, such as the IBM DFSMS implemented in the IBM MVS operating system.

[0023] The IBM DFSMS software is described in “z/OS V1R3 DFSMS Introduction,” IBM document no. SC26-7397-01, which document is incorporated herein by reference in its entirety. Storage management program 394 may include known storage management program functions, such as recall and migration. The storage management program 394 may be implemented within the operating system of the host computer 390 or as a separate, installed application program. Alternatively, storage management program 394 may include device drivers, backup software, and the like.

[0024] Referring now to FIG. 1, automated data storage and retrieval system 100 is shown having a first wall of storage slots 102 and a second wall of storage slots 104. Portable data storage media are individually stored in these storage slots. In certain embodiments, such data storage media are individually housed in portable container, i.e. a cartridge. Examples of such data storage media include magnetic tapes, magnetic disks of various types, optical disks of various types, electronic storage media, and the like.

[0025] Applicant's automated data storage and retrieval system includes one or more accessors, such as accessors 110 and 120. An accessor is a robotic device which accesses portable data storage media from first storage wall 102 or second storage wall 104, transports that accessed media to data storage devices 130/140 for reading and/or writing data thereon, and returns the media to a proper storage slot. In certain embodiments, data storage devices 130 (FIGS. 1, 2, 3) and 140 (FIGS. 1, 2, 3) comprise IBM TotalStorage® 3590 tape drives and the portable information storage media comprise magnetic tapes housed in IBM TotalStorage® 3590 tape cartridges.

[0026] Device 160 comprises a library manager. In certain of these embodiments, library controller 160 is integral with a computer. Operator input station 150 permits a user to communicate with Applicant's automated data storage and retrieval system 100. Power component 180 and power component 190 each comprise one or more power supply units which supply power to the individual components disposed within Applicant's automated data storage and retrieval system. Import/export station 172 includes access door 174 pivotably attached to the side of system 100. Portable data storage cartridges can be placed in the system, or in the alternative, removed from the system, via station 172/access door 174.

[0027] FIG. 2 shows system 200 which comprises another embodiment of Applicant's data storage and retrieval system. System 200 includes first storage wall 202 and second storage wall 204. Storage walls 202 and 204 each include a plurality of storage elements in which can be stored a plurality of portable data storage media. System 200 includes two or more data storage devices, such as devices 130 and 140. Data storage device 130/140 each comprise a floppy disk drive, an optical disk drive, a magnetic tape drive, an electronic media drive, and the like. System 200 further includes controller 160. System 200 further includes operator control panel 150 (not shown in FIG. 2).

[0028] System 200 further includes one or a plurality of portable data storage cartridges removeably disposed in one or more slots in storage walls 202/204. Each such cartridge contains a data storage medium internally disposed therein. Such data storage media includes optical media, magnetic media, tape media, electronic media, and combinations thereof.

[0029] System 200 also includes at least one robotic accessor 210 for transporting a designated portable data storage medium between a storage slot disposed in first wall 202 or second wall 204 and data storage device 130/140.

[0030] FIG. 4 provides a graphical overview of Applicants' method to maintain information by assigning one or more storage construct names to a logical volume and assigning one or more storage attributes to that logical volume using those one or more storage construct names. Host computer 390 creates a new dataset 400. Host 390 includes a set of Automatic Class Selection (“ACS”) routines which establish the data management policies for the new dataset, for one or more virtual volumes comprising that dataset, for writing those one or more virtual volumes to one or more physical volumes, and for management of those one or more volumes.

[0031] These ACS routines determine which information storage policies are assigned to each logical volume maintained by that host computer. These information policies include one or more data class policies 410, one or more storage class policies 420, one or more management class policies 430, and one or more storage group policies 440.

[0032] Data class storage policies include, for example, which recording format to use when writing volumes, which media cartridges to use, and the like. Storage class storage policies include, for example, whether to give the virtual volume preference to be removed or maintained on a DASD, such as DASD 310 (FIG. 3). Management class storage policies include, for example, whether a copy of the logical volume should be made immediately or whether to defer making that copy, selecting one or more information storage media to use when writing volumes, allocating a secondary stacked volume pool, and the like. Storage group storage policies include, for example, specifying a primary stacked volume pool for the logical volume, and the like.

[0033] After an ACS routine establishes a certain storage management policy for a logical volume, that ACS routine then assigns a storage construct name which indicates the selected storage management policy. In certain embodiments, each such storage construct name comprises an 8 byte designator.

[0034] In certain embodiments, host computer 390 (FIGS. 1, 2, 3, 4) comprises between zero and four ACS routines. In other embodiments, host computer 390 includes more than four ACS routines. In embodiments wherein host 390 includes four ACS routines, for example, host 390 may assign between zero and four storage construct names for new dataset 400. These zero to four storage construct names are passed by host 390 with new dataset 400 to an interconnected virtual tape system. Such an interconnected virtual tape system includes one or more virtual tape servers, such as VTS 300, and one or more data storage and retrieval systems, such as systems 100/200.

[0035] The virtual tape system includes a library manager, such a library manager 160 (FIGS. 1, 2). That library manager includes a library inventory 460. Library inventory 460 comprises a database. That inventory database 460 includes fields indicating the storage management policies selected for each virtual volume maintained on that virtual tape system. Thus, library database 460 includes a data class attribute field, a storage class attribute field, a management class attribute field, and a storage group attribute field.

[0036] Storage actions associated with each storage construct name are defined for a virtual tape system using an operator input station, such as operator input station 150 (FIG. 1), disposed in that virtual tape system. In certain embodiments, the operator input station is integral with the virtual tape server. In certain embodiments, the operator input station is integral with a data storage and retrieval system. In certain embodiments, the operator input station is remote from both the virtual tape server and the data storage and retrieval system. In these remote operator input station embodiments, operator input station 150 communicates with the virtual tape system using a serial interconnection, such as an RS-422 cable/RS-232 cable, a SCSI interconnection, an ethernet interconnection, a gigabit ethernet interconnection, a Fibre Channel interconnection, an ESCON interconnection, a local area network, a private wide area network, a public wide area network, a TCP/IP interconnection, combinations thereof, and the like.

[0037] When Applicants' virtual tape system writes a first file sequence to a logical volume, the storage construct names assigned to that virtual volume are stored in library inventory 460 as storage attributes assigned to that logical volume. If the virtual tape system subsequently accesses that logical volume, those storage attributes are recalled and used to determine storage management policies for that logical volume.

[0038] FIG. 5 summarizes the steps in certain embodiments of Applicants' method. Referring now to FIG. 5, in step 510 Applicants' method defines each of a plurality of storage construct names to indicate one or more requested storage management actions. In certain embodiments, one or more of these storage construct names are associated with each of the four information storage management policies described above.

[0039] In step 520, a host computer, such as host 390 (FIGS. 1, 2, 3, 4), forms a new dataset, such as dataset 400 (FIG. 4). Applicants' method transitions from step 520 to step 530 wherein the host assigns (N) construct names for the logical volume of step 510. In certain embodiments, (N) is zero. In alternative embodiments, (N) is selected from the group consisting of 1, 2, 3, and 4. In certain embodiments, (N) is greater than four. In certain embodiments, step 530 further includes using one or more automatic class selection routines to assign the (N) construct names.

[0040] Applicants' method transitions from step 530 to step 540 wherein the host computer sends a mount request to Applicants' virtual tape system. In step 540, the host computer provides the dataset of step 520 and the (N) construct names of step 530 to Applicants' virtual tape system. In certain embodiments, the mount request of step 540 comprises a Perform Library Function—Library Universal Mount command.

[0041] Applicants' method transitions from step 540 to step 605 (FIG. 6A). Referring now to FIG. 6A, in step 605 Applicants' method obtains (N) default storage construct names. In the certain embodiments, (N) is four. In certain embodiments, (N) is less than four. In certain embodiments, (N) is greater than 4. In the embodiment of FIGS. 6A and 6B, (N) is four.

[0042] In step 610, Applicants' method determines if the mount request of step 540 includes a storage class construct name. If Applicants' method determines in step 610 that a storage class construct name is not assigned, then Applicants' method transitions from step 610 to step 620 wherein Applicants' method assigns the default storage class construct name of step 605 to the logical volume. Applicant's method transitions from step 620 to step 630. Alternatively, if Applicants' method determines in step 610 that a storage class construct name is assigned, then Applicants' method transitions from step 610 to step 612 wherein Applicants' method determines if that assigned storage class construct name is defined.

[0043] If Applicant's method determines in step 612 that the assigned storage class construct name is defined, then Applicants' method transitions from step 612 to step 614 wherein Applicants' method assigns that storage class construct name as the storage class attribute for the logical volume. Alternatively, if Applicants' method determines in step 612 that the assigned storage class construct name is not defined, then Applicants' method transitions from step 612 to step 616 wherein Applicants' method determines if the undefined storage class construct name is to be automatically created. If Applicants' method determines in step 616 that the undefined storage class construct name is not to be automatically created, then Applicants' method transitions from step 616 to step 620. Alternatively, if Applicants' method determines in step 616 that the undefined storage class construct name is to be automatically created, then Applicants' method transitions from step 616 to step 618 wherein Applicants' method creates that storage class construct name and assigns default actions to that construct name. Applicants' method transitions from step 618 to step 614 where that newly created and defined storage class construct name is assigned as the storage class attribute for the logical volume. Applicants' method transitions from step 614 to step 630.

[0044] In step 630, Applicants' method determines if the mount request of step 540 includes a data class construct name. If Applicants' method determines in step 630 that a data class construct name is not assigned, then Applicants' method transitions from step 630 to step 640 wherein Applicants' method assigns the default data class construct name of step 605 to the logical volume. Applicant's method transitions from step 640 to step 650. Alternatively, if Applicants' method determines in step 630 that a data class construct name is assigned, then Applicants' method transitions from step 630 to step 632 wherein Applicants' method determines if that assigned data class construct name is defined.

[0045] If Applicant's method determines in step 632 that the assigned data class construct name is defined, then Applicants' method transitions from step 632 to step 634 wherein Applicants' method assigns that data class construct name as the data class attribute for the logical volume. Alternatively, if Applicants' method determines in step 632 that the assigned data class construct name is not defined, then Applicants' method transitions from step 632 to step 636 wherein Applicants' method determines if the undefined data class construct name is to be automatically created. If Applicants' method determines in step 636 that the undefined data class construct name is not to be automatically created, then Applicants' method transitions from step 636 to step 640. Alternatively, if Applicants' method determines in step 636 that the undefined data class construct name is to be automatically created, then Applicants' method transitions from step 636 to step 638 wherein Applicants' method creates that data class construct name and assigns default actions to that construct name. Applicants' method transitions from step 638 to step 634 where that newly created and defined data class construct name is assigned as the data class attribute for the logical volume. Applicants' method transitions from step 634 to step 650 (FIG. 6B).

[0046] Referring now to FIG. 6B, in step 650, Applicants' method determines if the mount request of step 540 includes a management class construct name. If Applicants' method determines in step 650 that a management class construct name is not assigned, then Applicants' method transitions from step 650 to step 660 wherein Applicants' method assigns the default management class construct name of step 605 to the logical volume. Applicant's method transitions from step 660 to step 670. Alternatively, if Applicants' method determines in step 650 that a management class construct name is assigned, then Applicants' method transitions from step 650 to step 652 wherein Applicants' method determines if that assigned management class construct name is defined.

[0047] If Applicant's method determines in step 652 that the assigned management class construct name is defined, then Applicants' method transitions from step 652 to step 654 wherein Applicants' method assigns that management class construct name as the management class attribute for the logical volume. Alternatively, if Applicants' method determines in step 652 that the assigned management class construct name is not defined, then Applicants' method transitions from step 652 to step 656 wherein Applicants' method determines if the undefined management class construct name is to be automatically created. If Applicants' method determines in step 656 that the undefined management class construct name is not to be automatically created, then Applicants' method transitions from step 656 to step 660. Alternatively, if Applicants' method determines in step 656 that the undefined management class construct name is to be automatically created, then Applicants' method transitions from step 656 to step 658 wherein Applicants' method creates that management class construct name and assigns default actions to that construct name. Applicants' method transitions from step 658 to step 654 wherein that newly created and defined management class construct name is assigned as the management class attribute for the logical volume. Applicants' method transitions from step 654 to step 670.

[0048] In step 670, Applicants' method determines if the mount request of step 540 includes a storage group construct name. If Applicants' method determines in step 670 that a storage group construct name is not assigned, then Applicants' method transitions from step 670 to step 680 wherein Applicants' method assigns the default storage group construct name of step 605 to the logical volume. Applicant's method transitions from step 680 to step 550 (FIG. 5). Alternatively, if Applicants' method determines in step 670 that a storage group construct name is assigned, then Applicants' method transitions from step 670 to step 672 wherein Applicants' method determines if that assigned storage group construct name is defined.

[0049] If Applicant's method determines in step 672 that the assigned storage group construct name is defined, then Applicants' method transitions from step 672 to step 674 wherein Applicants' method assigns that storage group construct name as the storage group attribute for the logical volume. Alternatively, if Applicants' method determines in step 672 that the assigned storage group construct name is not defined, then Applicants' method transitions from step 672 to step 676 wherein Applicants' method determines if the undefined storage group construct name is to be automatically created. If Applicants' method determines in step 676 that the undefined storage group construct name is not to be automatically created, then Applicants' method transitions from step 676 to step 680. Alternatively, if Applicants' method determines in step 676 that the undefined storage group construct name is to be automatically created, then Applicants' method transitions from step 676 to step 678 wherein Applicants' method creates that storage group construct name and assigns default actions to that construct name. Applicants' method transitions from step 678 to step 674 where that newly created and defined storage group construct name is assigned as the storage group attribute for the logical volume. Applicants' method transitions from step 674 to step 550 (FIG. 5).

[0050] Referring again to FIG. 5, in step 550 Applicants' method stores in the library inventory the (N) construct names of step 530 as (N) storage attributes assigned to the logical volume comprising the dataset of step 520. In certain embodiments, Applicants' method transitions from step 550 to step 580 wherein Applicants' method selects one or more storage management actions for the logical volume based upon the storage attributes of step 560. Applicants' method transitions from step 580 to step 590 wherein Applicants' method process the logical volume using the selected management actions of step 580.

[0051] In certain embodiments, Applicants' method transitions from step 550 to step 560 wherein the host computer updates the logical volume's storage attributes. In certain embodiments, step 560 includes using a Perform Library Function—Library Set Volume Attributes command. Applicants' method transitions from step 560 to step 580 wherein Applicants' method selects one or more storage management actions for the logical volume based upon the updated storage attributes of step 560.

[0052] Each time subsequent to the initial processing of the logical volume that Applicants' virtual tape system accesses the logical volume, in step 570 Applicants' method retrieves from the library inventory the storage attributes assigned to that logical volume. Applicants' method transitions from step 570 to step 580.

[0053] The embodiments of Applicants' method recited in FIGS. 5 and/or 6 may be implemented separately. For example, one embodiment may include only the steps of FIG. 5. Moreover, in certain embodiments, the individual steps recited in FIGS. 5 and/or 6 may be combined, eliminated, or reordered.

[0054] Applicants' invention includes an article of manufacture comprising a computer useable medium having computer readable program code disposed therein for maintaining information using a plurality of storage attributes. Applicants' invention further includes computer program products embodied as program code stored in one or more memory devices, such as a magnetic disk, a magnetic tape, or other non-volatile memory device, to maintain information using a plurality of storage attributes.

[0055] While the preferred embodiments of the present invention have been illustrated in detail, it should be apparent that modifications and adaptations to those embodiments may occur to one skilled in the art without departing from the scope of the present invention as set forth in the following claims.