Rebuilding the sampling cache
When MSDP is upgraded, the fingerprint lookup method does not change. If you want to use the new fingerprint lookup method predictive and sampling cache, you can configure it manually. Use the rebuild_scache script to rebuild the sampling cache during the maintenance window. It enhances the local deduplication ratio in post-upgrade environments when you enable predictive cache and sampling cache manually on local BYO, Flex, and Flex Worm environments.
The script is stored at the following location:
UNIX:
/usr/openv/pdde/pdag/scripts/rebuild_scache.shWindows:
install_path\Veritas\pdde\rebuild_scache.bat
You are not required to specify the log level. Logs are saved at the following location:
UNIX: /var/log/puredisk/<date and time>-rebuild-scache.log
Windows: C:\rebuild-scache.log
Consider the following recommendations when you run the script to rebuild the sampling cache.
After the upgrade, run this script immediately before running the backup tasks to rebuild the sampling cache.
Ensure that the predictive and sampling cache are enabled when the script is running.
For S3 interface for MSDP and universal share environments, rebuilding the sampling cache may affect deduplication ratios.
The script execution affects all backup jobs causing them to fail during the rebuilding process and the backup jobs are not performed.
If the backup job cannot be performed after the rebuilding process is complete, restart the MSDP.
When the script is initiated, ensure that it is successful. If it is terminated for some reason, run the script again.
If errors occur during the rebuilding process, run the script again.
To rebuild the sampling cache after an upgrade
- Enable predictive and sampling cache in
contentrouter.cfgandspa.cfg. - On the storage server, run the script:
UNIX:/usr/openv/pdde/pdag/scripts/rebuild_scache.sh
Windows:install_path\Program Files\Veritas\bin\rebuild_scache.bat
- Type y and press Enter to proceed. A warning about the job status is displayed.
- Type y and press Enter to initiate the process to rebuild. The script displays the rebuild state and percentage.
In the Flex worm environment, use deduplication shell to start the sampling cache rebuilding.
To rebuild the sampling cache from the deduplication shell
- Open an SSH session to the server.
- Run the following command for the initial sampling cache rebuilding.
setting rebuild-scache rebuild-sampling-cache
- See the sampling cache rebuilding status.
setting rebuild-scache rebuild-sampling-cache-status