Back Up and Recover Database
To assist your site with backup and recovery,
Viewprovides the following features:
To assist your site with backup and recovery,
Viewprovides the following features:
- Automatic backup of the current disk archival generation of SYSOUT and the master index during theViewbackup cycle
- Interim backups to minimize the time for which no backup exists on tape
- Restoration of a corrupted database with the SARDBASE RESTORE and SARRSP programs
- Restoration of a complete generation of SYSOUT data from tape to disk with the SARTDR program
- Tape mapping, copying, and salvaging with the SARTCP program
- Forward recovery, which provides recovery of SYSOUTs that were archived after the last backup of the database
During tape backup, the tape is cataloged when the tape is opened.
Backing Up the Database
As part of its backup cycle,
Viewoptionally backs up to tape the current disk archive generation of SYSOUT, along with the master index. The TBACKUP initialization parameter determines whether backup and DR processing are done.
Viewallows you to produce a duplicate of its backup tapes. A subparameter of the STORGRP
nparameters (unit2-name) determines whether tape duplexing is done.
Viewcan also create a DR tape if the DRTAPE parameter is set to YES or ACTIVE. Be aware of the following conditions:
- This tape is not a mirror image of the primary or duplex tape. The DR tape is written during the current Standard or Interim backup cycle and can be sent to the DR site.
- A new DR backup tape can be created for both the Standard and Interim backup cycles depending on how the DRMOD parameter is set, as follows:
- NEVER -- The backup cycle does not append reports to an existing DR backup tape.
- ALWAYS -- The backup cycle always appends reports to an existing DR backup tape until it becomes full.
- STD -- The backup cycle appends reports to an existing DR backup tape during Interim backup cycles and creates a new DR backup during Standard backup cycles.
If you define tape storage groups with the STORGRP
ninitialization parameters, we recommend that you make STORGRP1 the largest group, to enhance the performance of the backup cycle.
The master index contains the location and attributes of all archived SYSOUT; therefore, we recommend that you let
Viewback up the master index automatically. The master index is always backed up to the tape storage group defined by the initialization parameter STORGRP0.
All annotations are automatically backed up to tape during the normal backup cycle. Like resources for AFP and Xerox reports, the annotations remain on disk until the report is deleted from the system either manually or due to migration rules.
If a report is deleted from the system, annotations cannot be recovered with the tape utility.
Using Other Backup Products
If you use as backup product from another vendor (such as FDR, DFDSS, and so on) to back up theupdated during the backup, and that the entire database is backed up. Any references to
Viewdatabase, ensure that the database is
the databaserefer to the
Viewdatabase unless otherwise noted.
If a database spans multiple volumes, perform full volume backups. To restore the database, restore all data sets comprising the database from the same backup. If, for example, a volume containing part of the database crashes, and updates have occurred since the backup, you cannot restore only that volume.
If a tape management system is installed, do not override the
Viewtape retention criteria by the tape management system with respect to abnormal termination (ABENDS).
Backup and Recovery Guidelines
The following topics are the backup and recovery guidelines:
Forward Recovery and Interim Backups
If you have not activated forward recovery data set (RDS), all SYSOUT that was archived after the most recent standard or interim backup cannot be recovered. Therefore, if you do not use forward recovery data set, it is important to perform interim backups.
Damaged and Missing Tapes
The SARTCP utility can be used to salvage SYSOUT from a damaged tape. The utility maps the contents of copies, and reconstructs a backup archival tape. SARTSLST can be used to delete references to a missing tape.
Reloading from Tape
The SARTDR utility can be used to recreate and reload an entire disk archival generation from tape. Facilities are also available with the utility to add tape archival information again to the master index.
Recovery and Archival Resumption
The product automatically backs up the master index to tape as part of its backup cycle and maintains information on the backups in the recovery data set. In case of loss or destruction of the master index, the database can be restored from one of the backups using the RESTORE function of the SARDBASE program.
The SARDBASE RESTORE function does the following actions:
- Restores the master index from the appropriate backup tape
- Optionally copies the archived SYSOUT from the old database
SYSOUT archival cannot occur during the SARDBASE RESTORE preliminary phase (master index restore), but archival can be resumed during the data restore phase. The SARDBR17 console message notifies you when the preliminary phase has completed and informs you that you can bring up the
Viewstarted task to resume archival.
Alternatively, you can have SARDBASE RESTORE restore only the master index; then you can use SARRSP to restore SYSOUTs from tape. Archival can resume while SARRSP is running.
With forward recovery data set activated, all SYSOUT data archived by the
Viewstarted task is also stored in forward recovery data sets. To restore a database recover the SYSOUT data archived by the
afterthe last backup. (Forward recovery does not include SYSOUT written to the database by
You activate forward recovery data set with initialization parameters (RCVPRIM, RCVSEC, RCVSPACE, and RCVUNIT). When you specify values for these parameters and run SARINIT, the next
Viewbackup cycle allocates the forward recovery data sets. Subsequent backups delete old forward recovery data sets and allocate new ones.
To restore the database from backup tapes, the SYSOUTs residing in the forward recovery data sets are automatically written to the restored database.
If you do not have values for the forward recovery data set parameters, forward recovery data set is inactive.
Note:Forward recovery does not work for any reports picked up by the FSS Collectors. Forward recovery works only for reports picked up by the SARSTC.
Forward Recovery Data Set Format
The forward recovery data sets are compressed, manageable by SMS, and have a record format of U (undefined length records), a block size of 32760, and a DSORG of PS (physical sequential). The data set naming convention is:
nnnnnnnis a sequentially-incremented number that starts at 1.
Forward Recovery Data Set Operation
The forward recovery data set (RDS) stores the SYSOUT data that is archived during and after a backup cycle (standard or interim). It also stores the master control records (MCR), tape control records (TCR), and group control records (GCR) of the database.
If an RDS becomes full, the
Viewarchival task automatically creates a new RDS with the next sequential number. The starting and ending RDS numbers are tracked in the database.
Viewbackup begins, a new RDS with the next sequential number is automatically created. When the backup has successfully completed, the RDSs that contain data from before the current backup are deleted.
When SARDBASE RESTORE runs, it determines if there are any active RDSs. If active RDSs are found, RESTORE copies the SYSOUT data from the RDSs to the database it has restored automatically.
Forward recovery enables successful recovery from an unlimited number of nested failures, including failures which can occur during the recovery process.
Each RDS begins with control information. Because a SYSOUT group can consist of multiple JES data sets, the control information includes a pointer to the end of the last successfully stored JES data set.
If you want to restart the interrupted
Viewstarted task, the forward recovery data set storage process resumes with the JES presented next data set. If the interruption occurred while
Viewwas processing a JES data set in the middle of a SYSOUT group, JES presents the same "middle" data set to the
Viewarchival started task. The forward recovery data set storage process correctly appends that data set to the data sets that preceded it.
Forward Recovery Messages
Information messages and error messages about the forward recovery data sets are written using a WTO to the master console (ROUTCDE=1, DESC=7). Information messages identify the creation and deletion of the RDSs, and error messages identify any unusual conditions that arise during access of the RDSs.
Activating Forward Recovery
The space allocation (primary, secondary, and type) and unit name of the forward recovery data sets are defined and enabled with the following initialization parameters:
- RCVPRIM=nnnnSpecifies the primary space allocation for the forward recovery data sets.This parameter activates the forward recovery data set; with the next backup cycle, forward recovery data sets are created.
- RCVSEC=nnnnSpecifies the secondary space allocation for the forward recovery data sets.This optional parameter is used when the primary space allocation is exhausted.
- RCVSPACE=TRKS|CYLSSpecifies whether the space allocation for the forward recovery data sets are to be obtained in tracks (TRKS) or cylinders (CYLS).The default space allocation is tracks. This parameter is optional.
- RCVUNIT=unitSpecifies the unit name or unit type where the forward recovery data sets are to be allocated.This parameter is required for the forward recovery data set to be activated. Verify that the forward recovery data sets are not allocated on the same volumes on which the database resides.
Backup Cycle Consideration
If a backup cycle was
in progresswhen the started task was last executing, and if you restored the database using the forward recovery data set, resuming the started task results in an immediate backup cycle.
If no archival occurred since the last backup cycle, the MCR in the forward recovery data set indicates that a backup cycle was in progress. Resuming the started task results in an immediate backup cycle. If this is a primary backup, the generation number increments.
Database Recovery Utilities
The product provides several database utilities to facilitate the recovery process.
In the SARDBASE utility:
- The VERIFY control statement verifies and corrects the database (including broken pointer chains).
- The COPY control statement copies a database.
- The UNLOAD control statement unloads a database to tape.
- The LOAD control statement reloads a database from tape.
- The MERGE control statement merges one or more databases. (This requires the Expanded Retention Option.)
- The RESTORE control statement restores the database master index from tape (and optionally copies SYSOUT data from the old database).
The SARRCOV utility enables you to list or recreate the recovery data set.
The RESTORE control statement uses the recovery data set to process a database master index that spans multiple tape volumes.
The SARRSP utility enables you to repopulate the database from tape.
The SARTDR utility enables you to restore specific generations from tape.
SARTDR can also restore index information from tape.
The SARTSLST utility enables you to eliminate references to destroyed backup tapes.