DOCUMENTATION: More information about usage of the "nbcatsync" command in NetBackup 6.5.6 and 7.x

Article:TECH127922  |  Created: 2010-01-24  |  Updated: 2012-07-17  |  Article URL http://www.symantec.com/docs/TECH127922
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Technical Solution

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Issue



DOCUMENTATION: More information about usage of the "nbcatsync" command in NetBackup 6.5.6 and 7.x


Solution



The nbcatsync command reconciles the disk media ID information held in the meta-data of the NetBackup image database with the disk media ID information found in the NetBackup EMM database and is used in disaster recovery and device reconfiguration/replacement scenarios where the disk media IDs recorded in the EMM database are different to the disk media IDs that were in effect when the backups were created. 

The nbcatsync command can be used in any of the following scenarios:
  • During a DR (disaster recovery) of a master server at the original (primary) location where backups have been written to enterprise disk storage units such as Advanced Disk, Media Server Deduplication (MSDP), PureDisk Deduplication (PDDO) or OpenStorage (OST) devices.  In this scenario devices which are 'discovered' following the recovery of the master server may be assigned different disk media IDs to those used prior to the failure of the master server. 
  • During a disaster recovery activity at a DR site where media servers have access to the original enterprise disk storage (this may include situations in which disk storage has been moved to a DR site or media servers at the DR site have been connected to disk storage at the primary site).  In this scenario the media servers and disk devices must be discovered and configured in the EMM database of the DR master server and may be assigned different disk media IDs to those used prior to the failure of the original master server. 
  • When primary site AdvancedDisk, OST or PDDO devices are being replicated to a DR site outside of the control of NetBackup. In the case of AdvancedDisk a separate replication layer may be used.  In the case of OST the device vendor may provide the replication or it can be manually implemented.  In the case of PDDO replication at the PureDisk SPA layer may be used.  In this scenario the devices presented to media servers at the DR site and configured in the DR site master server's EMM database are likely to have different media IDs to those at the primary site.  
In all of these scenarios a copy of the image catalog must be recovered to the master server.  This can be recovered from a catalog backup that has been written to the enterprise disk storage or other storage (tape or BasicDisk) or, under the conditions defined for catalog replication, replicated from the primary master server. 
 
Note that nbcatsync uses the information from the most recent catalog backup entry (as recorded in the image database) to reconcile the disk media IDs.  This means that you must have a recent catalog backup in order to use the nbcatsync feature.  If the image catalog has been replicated or copied to the DR location it will only be possible to reconcile the images that were captured in the last catalog backup.  Even if replication is used do not neglect making catalog backups as this feature cannot be used without them.
 
The following steps explain how to use nbcatsync to reconcile the disk media IDs.  The steps that need to be followed depend on where the image database is being recovered from.  Where the catalog has been backed up to (and must be recovered from) enterprise disk storage start the process at step 1, where the catalog has been backed up to tape or BasicDisk start the process at step 3 and where the image database has been replicated or copied to the DR master server start the process at step 4.

1. Get the DR file for the catalog backup image you want to restore.

2. The DR file contains disk media ID references appropriate for the primary site which may need to be corrected before the restore operation at the DR site.

Run the following command at the DR site to fix the disk media ID references in the DR file so that bprecover can find the catalog backup image:

# nbcatsync -sync_dr_file <DR file>

3. Use bprecover with the updated DR file to restore the image-only catalog (i.e. don't perform a full restore).

4. Run the following command to fix the disk media ID references in the image headers restored from the catalog backup:

# nbcatsync -backupid <catalog_backup_id> [-dryrun]
 
Note : Specify the <catalog_backup_id> that contains the set of backup images recovered, this can be found in the DR file. This option enables nbcatsync to fix disk media ID references in the image headers that are restored from this catalog backup image ID.

Please be aware of the following notes: 
  • When nbcatsync finds an image from a source disk volume (e.g., volume A at the primary site) on disk volume B at the DR site, then all following images on volume A at the primary site are assumed to be available on disk volume B at DR site.  As such, the images are updated without actually looking for them on the disk volume(s).
  • The nbcatsync operation only affects information related to backups written to enterprise disk storage (AdvancedDisk, MSDP, PDDO and OST) and does not affect information related to backups written to BasicDisk or tape (including VTL).
  • The nbcatsync binary is not removed in the event of an upgrade from NetBackup 6.5.6 to NetBackup 7.0; however, the nbcatsync binary for 6.5.6 does not work in 7.0.  A 7.0.x port of nbcatsync is scheduled to be included in a future 7.0 Release Update (Etrack 1977608).
  • The nbcatsync will not recognise images that are outside of the original images/db location 7.1.0.4 (Etrack 2760448)
  • The nbcatsync will not recognise compressed images NetBackup 7.1.0.2 (Etrack 2683058) , the issue is resolved in NetBackup 7.1.0.4


 

Supplemental Materials

Value1977608

Legacy ID



347867


Article URL http://www.symantec.com/docs/TECH127922


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