Backup Accelerator

[NavGee]

Client would like to use accelerator and run full backups on standard and wintel policy types and do away with differential type of backup. I need to understand the engineering behind this as it need to be explained to Senior Technical Management team. How does expiration work when you are running full backups with accelerator due to change tracking etc. For instance daily full backup expires every two weeks. What does the next full accelerator backup do to track changes/reference point? Does it use it at the f.file?    If it does how does it use the f.file. I understand that accelerator uses block level for full backups and archive bit for differentials.

[Marianne · Accepted solution]

I seems your actual question is about deduplication and how cleanup works...

I assume that you are familiar with the basics of deduplication:  http://www.symantec.com/docs/HOWTO36285

Catalog references to expired backups is removed, but as long as there are links to actual data from unexpired backups, the deduped data is not removed.

This TN describes the dedupe cleanup process:  http://www.symantec.com/docs/TECH124914

Under normal operation, a sequence of regularly scheduled operations ensures that obsolete data segments are removed from the storage pools or deduplication pools automatically. Because each data segment may be owned by more than one backup image, segments are only removed when all the associated backups have expired.

Also see this excellent blog: Frequently Asked Questions on NetBackup Accelerator  

Hope this helps...