MEDIA
Operations Guide

3.4.2 Shadow medium

In some cases, when dealing with very important or sensitive data, it is useful to keep two copies at all times. A shadow medium is such a duplicate copy. Its implementation in the Librarian system is such that certain operations are automatically performed twice, once for the main medium and then again for the shadow medium.

Only the commands listed in in Table 3-1 are affected.

Table 3-1 Shadow medium commands
Command Action

* or $ Only write jobs create operations to the shadow medium.

SET Both media are changed

DELETE Both media are deleted

ASSIGN_TO Both media are assigned

RELEASE Both media are returned to the system

**Table 3-1 Shadow medium commands**
Command	Action
* or $	Only write jobs create operations to the shadow medium.
SET	Both media are changed
DELETE	Both media are deleted
ASSIGN_TO	Both media are assigned
RELEASE	Both media are returned to the system

Following is an example on how to implement this.

MEDIA UNKNOWN SET/COMMENT="DUPLICATE MASTER TAPE" 1234 allocated MEDIA 2333 SET/SHADOW=1234 MEDIA 2333 SET/DENSITY=800/LOG Media 2333 modified Media 1234 modified

3.4.3 Attached volumes

Volume sets of up to 45 volumes can be created. Once a volume is part of a volume set, the DIRECTORY command will only display master volume information. This master entry is the volume set control entry. All directory contents information is kept with this master volume. To display the header information about an attached media, the ATTACHED qualifier must be added to the command. The commands listed Table 3-2 can modify volume sets.

Table 3-2 Attached volume commands
Command Action

DETACH Remove a volume from a volume set

ATTACH_TO Add a volume to a volume set

**Table 3-2 Attached volume commands**
Command	Action
DETACH	Remove a volume from a volume set
ATTACH_TO	Add a volume to a volume set

Below is an example of how to bind four volumes together and then detach them.

MEDIA 21,22,23 ATTACH_TO 20 MEDIA 21,22,23 DETACH

The volume set information is used during the mount operation to supply VMS with the list of volumes to use. It is important to note that VMS only supports the multi-volume sets for ANSI MOUNTED volumes. The only exception is in cases like BACKUP where the program itself takes care of the volume changing.

3.4.4 Directory update procedures

The update procedure extracts from the removable media all directory information and places it in the on-line library database. Whenever a write job is created, the necessary commands are included to do a directory update. If the device commands are used directly, then it is up to the user to add the UPDATE command as needed. The status flags indicate if the general nature of the media is tape or disk. The update flag indicates which type of update is being used. Different procedures are used for each type.

3.4.4.1 Tape update procedures

There are five different procedures available for tapes. The different procedures are listed in Table 3-3.

Table 3-3 Tape update procedures
Name Meaning

Auto-select group

ANSI Normal VAX/VMS tape labeling

IBM_SL IBM EBCDIC labeling

DOS DOS-11 label format

UNLABELED No labels present

Locked in group

SIZER Determine amount of tape used

NONE No update performed

**Table 3-3 Tape update procedures**
Name	Meaning
Auto-select group
ANSI	Normal VAX/VMS tape labeling
IBM_SL	IBM EBCDIC labeling
DOS	DOS-11 label format
UNLABELED	No labels present
Locked in group
SIZER	Determine amount of tape used
NONE	No update performed

Of these ANSI, IBM_SL, DOS, and UNLABELED procedures will allow the procedure to be changed if it is found that the tape labeling is not as first indicated. The SIZER procedure reads the tape to estimate how much tape was actually used; no other operation is performed. The NONE mode will prevent any automatic update processing from being done.

Multiple volumes are supported for all but the DOS and UNLABELED procedures.

3.4.4.2 Disk update procedures

There are two different procedures available for disks. These methods are summarized in Table 3-4.

Table 3-4 Disk update procedures
Name Meaning

FILES11 Normal RMS disk directory structure

SIZER Just determine the number of free/used blocks

NONE No update performed

**Table 3-4 Disk update procedures**
Name	Meaning
FILES11	Normal RMS disk directory structure
SIZER	Just determine the number of free/used blocks
NONE	No update performed

Multiple volume update procedures for disks are not supported. A multiple volume disk set can only be mounted foreign and used in conjunction with programs like BACKUP.

3.4.5 Sharable disk volumes

Two types of allocation pools are recognized by the MANAGER. They are allocated for the exclusive use and allocated for shared use. All TAPE type of devices can only be allocated for exclusive use. DISK types can be allocate either shared or exclusively. Once a disk has been allocated as sharable, multiple jobs that require the same disk can execute.

To use this feature for your removable disk packs. First modify the mount characteristics to indicate SHARED.

MEDIA disk SET/MOUNT=SHARED

Change the batch queue associated with these disks to allow multiple jobs.

START/QUEUE/JOB_LIMIT=4 queue

When a MEDIA JOB is created it is placed in the correct queue for execution. When the job becomes active it is allowed to proceed if the required volume is found already on-line and indicated as shareable. If the volume is not on-line an appropriate drive is allocated and the OPERATOR is requested to load the pack.

This sharable use process works in the same fashion for either a single CPU or a Cluster.

3.5 Managing VAULT

This section deals with the general characteristics of the VAULT Saveset Manager.The topics covered are:

Components of a Backup
Typical restore sequence
Database management

The purpose of the VAULT Saveset Manager is to allow users to easily identify and restore any files that have been copied onto off-line storage by the system during normal, full, incremental and unloading backups.

On-line directory: A directory structure which parallels the on-line directory is kept for all files that are in the backup system. Just as the VMS DIRECTORY command gives a listing of the on-line files, the VAULT command gives a listing of all the off-line files in the backup system for a particular directory or sub-directory.
File protection: A user can only view or request a restoration of files that he has access to.The UIC based protection attributes are maintained in the VAULT database.
Simple restore: By simply adding the /RESTORE qualifier, any file found in the VAULT database will be restored. The restore request will automatically create a MEDIA job that will request the operator to mount the proper tape or disk and restore the specified files.
VMS BACKUP format: All backup tapes and files are created using VMS BACKUP thus allowing fully portable tape formats and compatability with all other VAX sites.
Backups: Regular backups, either incremental or full, are easily automated using the SCHEDULE⁴²
system or manually using BCKMGR. After each backup is executed, the VAULT database is updated. From that moment on, all users can easily identify and selectively restore any file that exists on a backup tape.

3.5.1 Components of a backup

All backups follow a similar sequence of commands. The various steps are listed below with the associated portions of the MEDIA Librarian.

Create backup jobs on a regular schedule; for example, incremental backups each day. This can be done via the SCHEDULE System or manually using BCKMGR.
Search and write the selected files to an off-line disk or tape. This is done using the VMS BACKUP utility.
Track the location and manage the media that have been used for backups and other purposes. This is done via the MEDIA program.
Allow users and managers to easily identify and restore selected files from the backup tapes. This is done via the VAULT Saveset Manager.

3.5.2 Typical restore sequence

Frequently, a user will discover that in he has accidentally deleted a file or that the archive system has off-loaded a file to tape. Below is an illustration of what would be required to restore a particular file. All these operations can easily be performed by the user without compromising the system security or obtaining access to the system backups.

3.5.2.1 Locate the file

First, locate the file by using the VAULT command. The general user can issue this command to determine what files are contained in the backup system on his behalf. All current default device and directory specifications are processed in the same fashion as the VMS DIRECTORY command. A typical VAULT command to list a directory is illustrated below:

$ VAULT SYS$LOGIN:* Vault directory DBA0:[SMITH] LOGIN.COM;1 BATCH23.LOG;1 BATCH23.LOG;2 TEST.COM;1 MAIL.MAI;2 Total of 5 files $ VAULT Vault directory DBA0:[SMITH.DATA.TEST1] PLOT.FOR;1 PLOT.FOR;2 PLOT.FOR;3 TEST3.DAT;1 TESTE.DAT;2 UX22.DAT;1 UX22.DAT;1 UX33.DAT;1 ZZZZTEST.DAT;1 Total of 9 files $ VAULT/DATE/COMMENT/SINCE=1-JUL-1996 * Vault directory DBA0:[SMITH.DATA.TEST1] PLOT.FOR;1 26-AUG-1996 11:18 Incremental backup PLOT.FOR;2 27-AUG-1996 12:00 Incremental backup PLOT.FOR;2 1-OCT-1996 14:00 Moved to archives TEST3.DAT;1 10-AUG-1996 00:10 Full system backup TEST3.DAT;2 11-AUG-1996 13:00 Incremental backup

3.5.2.2 Restore the file

To restore a particular file, the user can then issue the following type of command using the /RESTORE qualifier. This generates a request to the system. The system then generates a job with the needed privileges to access the required backup medium. Some typical commands to request a file to be restored are listed below:

$ VAULT/RESTORE TEST3.DAT;1 $ VAULT/RESTORE/CONFIRM PLOT.FOR Restore DBA0:[SMITH.DATA.TEST1]PLOT.FOR;2 [Y/N] :N Restore DBA0:[SMITH.DATA.TEST1]PLOT.FOR;2 [Y/N] :Y Restore DBA0:[SMITH.DATA.TEST1]PLOT.FOR;3 [Y/N] :N $ VAULT/RESTORE/LOG SYS$MANAGER:ACCOUNTNG.DAT;3 Restoring DBA0:[SYS0.SYSMGR]ACCOUNTNG.DAT;3

3.5.2.3 File attributes

The internal structure of the VAULT database closely parallels the VMS DIRECTORY structure. The full file attributes are kept and special linkages are created for directory file pointers. The overall design of VAULT is to minimize disk usage and maximize execution speed.

$ VAULT/FULL PLOT.FOR;1 DBA0:[SMITH.DATA.TEST1]PLOT.FOR;1 Size: 130 Created: 1-AUG-1996 11:18 Owner: [ISE,SMITH] Revised: 29-AUG-1996 08:30 Protection: Expires: (not set) (S:RWED,O:RWED,G,W) Backup: 1-AUG-1996 14:34 Record size: 80 Vaulted: 30-AUG-1996 17:01 Record format: Sequential, variable size Note: Incremental backup Location: 1205(DBA0.BCK/2/1206)

3.5.3 Vault database management

Many features exist to facilitate managing the VAULT database. Most of these commands are designed to be included in the backup jobs that create the backup media. The basic operations that can be performed by the manager to update and control the VAULT database are:

ADD: The ADD function will add all the files contained on a particular medium. The contents information is extracted from the MEDIA database and inserted into the VAULT database. In the process of doing this, all the attributes from the on-line file header are also extracted and inserted in the VAULT database. During the ADD process, all the files found on the medium can optionally be deleted from the on-line storage.
REMOVE: The REMOVE function removes all file entries associated with a particular medium from the VAULT database. Once a medium is added to the VAULT database, it cannot be removed from the MEDIA library without first removing it from the VAULT database.
DELETE: The DELETE function will mark a specific file as deleted in the VAULT database. All files marked as deleted will not be displayed in normal directory operations. The DELETE marks are used by the RELEASE function to determine if a particular medium can be removed from the database. i.e. all files on it are marked as deleted.
RELEASE: The RELEASE function checks to see if all files associated with a particular medium are marked for delete. If they are, then the medium is RELEASED back to the system and it is removed from the VAULT database.
SORT: The SORT function will sort the VAULT database. This will place all files in alphabetical order in descending version number sequence.

3.5.4 Adding to the VAULT database

A whole medium at a time is added into the VAULT database. The medium must be cataloged and have a BJL file for its contents file to be added into the VAULT database. Typically this operation would be embedded inside a backup procedure. The BCKMGR_MAINT.COM procedure can be used to create this type of command procedure.

$ BCKMGR PICK_MEDIA/LOG $ REQUEST "Backup of _DBA0: started, use volumes ''MEDIA_LIST'" $ BACKUP/JOURNAL/IGNORE=INTERLOCK/FAST _DBA0:/IMAGE - MEDIA:DBA0.BCK/RECORD/LABEL=('MEDIA_LIST') $ BCKMGR ADD_IN_JOURNAL $ VAULT/ADD/LOG/ONLINE/COMM="Full backup"/DEVICE=DBA0: 'MEDIA_EXT' $ VAULT/SORT _DBA0:[*...] $ BCKMGR COMPLETED 'JOB_NAME'

3.5.5 File placement

The VAULT database is composed of many files all having the extension ADR. One ADR file corresponds to one RMS directory file. Thus depending on your system size, the number of these files can be large. The default is to place all these files into the MEDIA_LIBRARY directory. This may or may not be appropriate for your installation.

The placement of the ADR files is controlled by a series of parameters and/or logical names. If both the parameter and the equivalent logical name are present, the parameter will be used. The steps listed in Table 3-5 are taken to locate a particular ADR file.

Table 3-5 VAULT file positioning
Description Parameter name Logical name

1. Locate the MEDIA Library database location by using: CENTRAL MEDIA_LIBRARY:

2. Locate the VAULT database location by using: (If neither is defined, the MEDIA Library database location is used.) VLT_CENTRAL VAULT_LIBRARY:

3. The name of the source disk is used to determine the exact device-directory location of the ADR file, using the the below logical name or parameter value. (Where "nnnnn" is the disk logical volume name. Typically something like DISK$SYS0. If neither is defined, the VAULT database location is used.) VDISK_nnnnn VAULT_nnnnn

**Table 3-5 VAULT file positioning**
Description	Parameter name	Logical name
1. Locate the MEDIA Library database location by using:	CENTRAL	MEDIA_LIBRARY:
2. Locate the VAULT database location by using: (If neither is defined, the MEDIA Library database location is used.)	VLT_CENTRAL	VAULT_LIBRARY:
3. The name of the source disk is used to determine the exact device-directory location of the ADR file, using the the below logical name or parameter value. (Where "nnnnn" is the disk logical volume name. Typically something like DISK$SYS0. If neither is defined, the VAULT database location is used.)	VDISK_nnnnn	VAULT_nnnnn

We recommend that you place the various ADR files on the disk to which they pertain. For example, for a three disk system, where the volume names are SYS0, SYS1 and SYS2 set up the following parameter values.

$ MEDIAS MEDIAS> SET VDISK_DISK$SYS0 == "DISK$SYS0:[VAULT]" MEDIAS> SET VDISK_DISK$SYS1 == "DISK$SYS1:[VAULT]" MEDIAS> SET VDISK_DISK$SYS2 == "DISK$SYS2:[VAULT]"

VDISK parameters are automatically setup by the use of the BCKMGR_MAINT.COM procedure. It is set to point to a subdirectory of the MEDIA_LIBRARY directory.

If you do not know what your logical volume names are the following DCL command can easily supply it.

$ WRITE SYS$OUTPUT "''F$GETDVI("DUA0:","LOGVOLNAM")'"

Note

⁴² Available as a separate product.

Contents

Index

MEDIA Operations Guide

3.4.2 Shadow medium

3.5.2 Typical restore sequence

3.5.4 Adding to the VAULT database

42 Available as a separate product.

MEDIA
Operations Guide

⁴² Available as a separate product.