Specifying before, after, and nobackuptag flags to increase index lookup speed
The
Avamar Plug-in for Oracle uses the
avtar --history command to perform index lookups. This command can sometimes run slowly. To increase the index lookup speed, you can specify the
--before,
--after, and
--nobackuptag flags with the
send command.
About this task
The
Avamar Plug-in for Oracle runs the
avtar --history command for each CLI backup and for each backup a restore retrieves. When a backup or restore includes hundreds of backups, the
avtar --history command might take hours to run.
The
avtar --history command supports two time-range CLI flags, as well as the
--nobackuptag flag:
The
--before flag instructs the
avtar process to search only for backups that were created before the time specified by the
--before flag.
The
--after flag instructs the
avtar process to search only for backups that were created after the time specified by the
--after flag.
The
--nobackuptag flag can improve performance because the
Avamar Plug-in for Oracle library,
libobk_avamar.x, automatically sets the
--backuptag flag to search backups. This may cause slow restore performance due to
avtar --history failing and retrying. The
--nobackuptag flag can be used to avoid failing history searches.
The
Avamar Plug-in for Oracle library,
libobk_avamar.x, enables you to set the
--before,
--after, and
--nobackuptag flags for operations that perform an index lookup. The
libobk_avamar.x uses these flags to increase index lookup performance.
Procedure
Do not set the
--before or
--after flags for backups. The
libobk_avamar.x automatically sets these flags to the backup start time, which enables the backup index lookup to search only for backups that are created after the backup began.
Set the
--before,
--after, or
--nobackuptag flags for restores with the
send command in an RMAN script. The following RMAN script shows how to set these flags:
Use the following time format for the
--before and
--after flags:
YYYY-MM-DDHH:MM:SS
NOTE:The smaller the time range between the
--before and
--after flags, the faster the searches.
In addition to the
--before and
--after flags, use the
--nohist flag to disable all index lookups for all operations. Set the
--nohist flag with the
send
command in an RMAN script:
NOTE:When you use the
--nohist
flag during a backup or restore operation, and if the backup piece label name contains more than 48 characters, the operation fails because of the Avamar server's user accounting system limitation.
Use the
–noduplicatecheck flag, to disable index lookups only for backups to disable duplicate name checks. Set the --noduplicatecheck flag with the send command in an RMAN script:
The
--noduplicatecheck
flag does not require a value and is only relevant for backups that are performed from RMAN CLI without a taskfile. Because use of the
--noduplicatecheck flag disables the check for duplicate names in the Avamar server, best practices are to name backup pieces in the RMAN script, for example:
%d_%U, to that ensure that each backup piece is unique.
Results
When a backup or restore specifies all four flags, the
--nohist flag takes precedence. The
--before and
--after flags are ignored.
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