Video Screencast Help

Reducing Media Set Size

Created: 19 Dec 2013 | 2 comments

I am using Backup Exec 2010 R3.  I have a media set that was set to hold 8 weeks of retetention.  I now need space cleared on the drive its on (its not full yet, but i need space).  I have lowered the retention to 4 weeks.  The previous 4 weeks is not marked as over writable, but i need to delete it to free up space.  I beleive Backup Exec is using deduplication.  How do I safely remove the data 4-8 weeks to free up space?

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Colin Weaver's picture

Sorry but if deduplication is involved then you may not be able to free up space

When deduplication is involved the media shown in Backup Exec console is logical with deduplication managing the actual files stored on disk.

Every backup is analyzed on a 'chunk' by 'chunk' basis existing chunks end up having their related backups sets records increased by one, new chunks create a new entry with only one related backup set (initially) with more being added when further backups run

When you delete a piece of media from Backup Exec the logical entry for the media is deleted, and the link between the backup set and the chunks is reduced by one. A chunk will ONLY be reclaimed once all backups sets relating to that chunk are deleted which really means the likelihood of deleting some media from Backup Exec actually recovering lots of disk space is small.

Also as you state you have enough space if the reason you want to reduce it is to use part of the volume for something else then please be aware that best practices for Deduplication is that the storage used for Deduplication is not used for other activities.

lmosla's picture

In addition to Colin Weaver, see this document for more information on reclaiming space