Vacuum and Compaction
The Server Backup Manager offers two cleanup methods that can be used to maintain Disk Safe size and performance. They work in similar ways, but have different considerations, and produce different results.
This quick guide is meant to help you decide which disk safe cleanup method is best for you.
Full Vacuum guide available here.
The Vacuum task removes free pages from the disk safe, by moving full and partially used pages to the front of the file, and truncating the file at the point free pages begin. It removes unused space and shrinks the Disk Safe file.
Vacuum should only be used if a Disk Safe has grown to a large size, and freeing up disk space is the top concern.
Vacuum should not be used to increase Disk Safe performance. Vacuuming a disk safe one or more times can increase fragmentation, and result in a performance reduction.
Full Compaction guide available here.
Compaction makes a copy of your Disk Safe which replaces the original. During the copy process, free pages are removed to reduce the Disk Safe footprint, and the blocks are re-ordered to help improve backup and restore performance.
Compaction is most effective on Disk Safes where backup and restore performance has gradually decreased over time. Disk Safes that have had hundreds or thousands of backups stored and merged out of them over time are good candidates for Compaction.
- Compaction tasks are I/O intensive. Avoid compacting during peak backup hours when system resources are most needed to complete scheduled replication tasks.
- Compaction makes a full copy of the Disk Safe. Avoid using it on systems with low available free space.
- Compaction can take many hours or even days to complete on larger Disk Safes. Do not expect instant results.