Chapter 4. On-Demand Backups

NetWorker BusinesSuite Module for Informix provides scheduled, automated backup services for your OnLine Dynamic Server.  The NetWorker XBSA library provided with BusinesSuite Module for Informix also enables you to configure on-demand backups using the ON-Bar command-line interface.  The command examples presented in this chapter are in C–shell format.

Performing On-Demand Backups Using ON-Bar

ON-Bar connects to NetWorker through an XBSA API, which passes dbobjects through a shared library.  When you set up a system running OnLine Dynamic Server as a client of the NetWorker server, several variable settings are configured and passed to ON-Bar by the nsrdbmi script, which is invoked during a scheduled backup.

To perform an on-demand NetWorker backup using the ON-Bar command-line interface, you must first provide values for several required NetWorker XBSA environment variables.  The environment variables can be set through the command line interface or a script in $INFORMIXDIR.

Caution: If you do not provide explicit settings for the required NetWorker XBSA variables, on–demand NetWorker backups default to the settings for a regular NetWorker filesystem backup, using NetWorker default configurations.  This means that the log files, dbspaces, and blobspaces may be directed to the NetWorker “Default” media pool.  See Appendix A, “XBSA Environment Variables” for the NetWorker XBSA environment variable default settings.

ON-Bar Backups and NetWorker Indexes

The NetWorker server's savegrp program invokes a level 9 backup of the client indexes and the NetWorker server's bootstrap save set each time a scheduled backup completes.  The savegrp program is invoked only during a scheduled backup.

When you use the ON-Bar command line interface to perform an on–demand backup of OnLine Dynamic Server, the NetWorker client indexes for OnLine Dynamic Server and the NetWorker server's bootstrap save set are not backed up.  If you never perform scheduled NetWorker backups, the NetWorker client indexes and NetWorker server's bootstrap save set are never backed up.

The client indexes and the NetWorker server's bootstrap save set are vital for restoring data to OnLine Dynamic Server in the event of a disaster.  Performing regular, scheduled NetWorker backups of OnLine Dynamic Server provides maximum protection for your critical data.

Caution: If you never perform scheduled backups using NetWorker, you will not have backups of the client's indexes and server's bootstrap save set for use in the event of a catastrophic disaster.

Required NetWorker XBSA Variables for Data Backups

Substitute the values shown for the NetWorker XBSA variables in the following example with the same ones you assigned for scheduled NetWorker backups of OnLine Dynamic Server:

setenv NSR_SERVER networker_servername 
setenv NSR_DATA_VOLUME_POOL dbmidata_pool 
setenv NSR_LOG_VOLUME_POOL dbmilog_pool 

Caution: If you do not specify a value for the NetWorker XBSA variable NSR_SERVER before issuing an ON-Bar command, NetWorker searches the network for the correct server to use.  Setting the NSR_SERVER variable helps avoid a potential delay in the backup process.

If you do not have a NetWorker configuration for scheduled backups of OnLine Dynamic Server, you can substitute the values for the required NetWorker XBSA variables with any valid NetWorker XBSA value.  See Appendix A, “XBSA Environment Variables” for information about the NetWorker XBSA environment variables and their valid values.

Note: You must be logged in as informix or root to use ON-Bar commands for on–demand NetWorker backups of OnLine Dynamic Server dbspaces, blobspaces or logical log files.

Example of an On-Demand Backup Command

The commands shown in the following example

  • perform a level 0 (NetWorker “full”) backup of the dbobject “dbspace01” on an OnLine Dynamic Server instance named “venus”

  • back up all full logical log files associated with “dbspace01”

  • close the current logical log

  • back up the closed logical log

    setenv NSR_SERVER jupiter 
    onbar -b -L 0 dbspace01 
    onbar -l -c 

NetWorker XBSA translates the instance's dbobject “dbspace01” and the level 0 specification into “INFORMIX:/venus/dbspace01/0” for the save set entry in the NetWorker server's online file and media indexes.  The last field in the save set entry for a manually backed-up dbobject indicates the backup level.

For details on using ON-Bar commands, and backup strategy suggestions for protecting OnLine Dynamic Server data, refer to “Using ON-Bar” in the INFORMIX–Online Dynamic Server Backup and Restore Guide provided with OnLine Dynamic Server.

Performing Continuous Logical Log Backups

ON-Bar is configured, by default, to back up logical logs automatically once the log file is filled.  After the log file is successfully backed up, ON-Bar closes the file, frees the space used by the file, and opens a new file for transaction logging.  Log file backups are always performed as a “full” backup (ON-Bar level 0).

Caution: For continuous log backups, Informix recommends dedicating a backup device to the logical log backup process.  This ensures that a device on the backup server is always available to receive logical log data.

Required NetWorker XBSA Variables for Continuous Log Backups

If you choose to maintain continuous backups of your logical logs, modify the OnLine Dynamic Server $INFORMIXDIR/etc/ script to include the NetWorker XBSA variables.  Assign the same values used for scheduled NetWorker backups of the log files associated with the OnLine Dynamic Server instance:

NSR_SERVER = networker_servername 
NSR_LOG_VOLUME_POOL = dbmilog_pool 
export NSR_SERVER 

If you created a customized nsrdbmi script and modified values for other NetWorker XBSA variables, be sure to include the modified variables and assigned values in the $INFORMIXDIR/etc/ script.  Otherwise, the NetWorker XBSA variables default to the values described in Appendix A, “XBSA Environment Variables.”

Note: Even if you do not use logging for OnLine Dynamic Server, a log file containing administrative information such as checkpoint records and additions and deletions of chunks is maintained.  Backups of this type of log file are very small.  Even if you do not use logging, maintaining backups of the abbreviated log file are required to restore data from dbspace backups.  The only type of backup that can be restored without logs is a whole-system backup.

Chapter 5 provides information on restoring backed up data to OnLine Dynamic Server.