Following are recommended best practices for using AOFO and the Symantec Volume Snapshot Provider (VSP):
Ideally, allow AOFO exclusive use of a disk. This disk should not have any user data, should never be backed up, and should have the AOFO cache file location directed to it.
Make sure there is sufficient space on the disk to encompass all of the changed data. Changed data can include user files, system files, and the NTFS Master File Table (MFT).
Exclude the cache file from real-time virus scanning software. Do not run regular scans or disk utilities such as scan disk or defragmenters during backups with AOFO.
To prevent the VSP cache file from excessively large growth on a disk during a backup operation, avoid the following:
Create backup-to-disk folders on a different physical disk than the disk you want to back up. For example, if AOFO is used to snap volumes during a backup, and if the destination device is a backup-to-disk folder, the backup-to-disk folder should be on a separate volume that is not being snapped.
About the Advanced Open File Option
Requirements for using Advanced Open File Option
Setting defaults for the Advanced Open File Option for backup jobs
Changing the default settings for the Symantec Volume Snapshot Provider
Adjusting the Symantec Volume Snapshot Provider cache file size
Checking the job log when using the Advanced Open File Option