Temporary log files (RstDbLog and Failarch) in IBM TSM

A database backup includes a database image and associated recovery-log files. During a database restore, the recovery-log files are temporarily stored in a subdirectory called RstDbLog. Log files that are created during day-to-day operations and that cannot be stored in the active log directory or in the archive log directory can be temporarily stored in a subdirectory called failarch.

RstDbLog and Failarch Overview

To specify the location of subdirectories RstDbLog and failarch, use the ARCHFAILOVERLOGDIRECTORY server option. The Tivoli Storage Manager server creates the RstDbLog and failarch subdirectories in the directory that is specified by the server option. If you use this method, use a file system that is different from the file system that is specified by the ACTIVELOGDIRECTORY and ARCHLOGDIRECTORY parameters.

If you do not set the ARCHFAILOVERLOGDIRECTORY option, the Tivoli Storage Manager server creates the RstDbLog and failarch subdirectories automatically in the directory that is specified for the ARCHLOGDIRECTORY parameter on the DSMSERV FORMAT or DSMSERV LOADFORMAT command. You must specify the ARCHLOGDIRECTORY parameter for these commands.

Instead of using the server option to specify the location of the subdirectories, you can use the ARCHFAILOVERLOGDIRECTORY parameter in the DSMSERV FORMAT or DSMSERV LOADFORMAT command.

Consider using the ARCHFAILOVERLOGDIRECTORY server option or parameter to specify the location of RstDbLog and failarch subdirectories in a dedicated archive-failover-log directory, rather than allowing the server to automatically create the two subdirectories under the archive log directory. If the archive log directory becomes full, it can limit the amount of space that is available for archived log files. If you must use the archive log directory, consider increasing its size to accommodate both the RstDbLog and failarch directories.

For a database restore operation, you can specify the location of the RstDbLog subdirectory, but not the failarch subdirectory, by using the RECOVERYDIR parameter on the DSMSERV RESTORE DB command. Consider allocating a relatively large amount of temporary disk space for the restore operation. Because database restore operations occur relatively infrequently, the RstDbLog subdirectory can contain many logs from backup volumes that are stored in preparation for pending rollforward-restore processing.

Also Read: How to increase or decrease TSM DB, active log and archive log size ?

If you are using ARCHFAILOVERLOGDIRECTORY server option

If you specify the ARCHFAILOVERLOGDIRECTORY server option or the ARCHFAILOVERLOGDIRECTORY parameter in the DSMSERV FORMAT or DSMSERV LOADFORMAT command, the server creates the RstDbLog and failarch subdirectories in the archive failover-log directory.

dsmserv format dbdir=/tsmdb001 activelogdirectory=/home/tsminst1/inst1/activelog archlogdirectory=/home/tsminst1/inst1/archlog archfailoverlogdirectory=/home/tsminst1/inst1/archlogfailover

The server also updates the DB2® parameter OVERFLOWLOGPATH that points to the RstDbLog subdirectory and the DB2 parameter FAILARCHPATH, that points to the failarch subdirectory. For example, suppose that you specify archlogfailover as the value of the ARCHFAILOVERLOGDIRECTORY parameter on the DSMSERV FORMAT command:

If you are using ARCHLOGDIRECTORY server option

If you do not set the ARCHFAILOVERLOGDIRECTORY parameter or server option, the server automatically creates the subdirectories RstDbLog and failarch in

the directory that is specified for the ARCHLOGDIRECTORY parameter. In addition, the server updates the DB2 parameters OVERFLOWLOGPATH and FAILARCHPATH to

point to those subdirectories.

Also Read: Follow these steps if you need to change the TSM DB and Recovery Log filesystems

For example, suppose that you specify a value of archlog for the ARCHLOGDIRECTORY parameter in a DSMSERV FORMAT command. You do not specify the ARCHFAILOVERLOGDIRECTORY parameter:

dsmserv format dbdir=/tsmdb001 activelogdirectory=/home/tsminst1/inst1/activelog archlogdirectory=/home/tsminst1/inst1/archlog

If you are using the RECOVERYDIR server option

For a database restore operation, you can specify a temporary location for the RstDbLog subdirectory by using the RECOVERYDIR parameter on the DSMSERV RESTORE DB command. The Tivoli Storage Manager server creates the RstDbLog subdirectory in the directory that is specified by that parameter. The server does not create the failarch subdirectory. The server also updates the DB2 parameter, OVERFLOWLOGPATH, that points to RstDbLog.

Also Read: Taking TSM server DB backup when the server is down

Restriction: The location specified by the RECOVERYDIR parameter takes precedence over the location specified by the ARCHFAILOVERLOGDIRECTORY or ARCHLOGDIRECTORY server option or parameter.

For example, for a point-in-time database restore, you can issue the following command:

dsmserv restore db todate=5/12/2011 totime=14:45 recoverydir=/home/tsminst1/inst1/recovery

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Temporary log files (RstDbLog and Failarch) in IBM TSM

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