10-27-2009 08:37 AM
10-27-2009 08:47 AM
1. For file level backup and restore, there is really no disadvantage as such of using AOFO. It is really helpful in backup of open files. in terms of time or space also, VSS is claimed to be faster by Microsoft, so that is really not an issue. So, for file level backup and restore, AOFO is definitely recommended.
2. Snapshot contains all the write activity coming to disk, while the backup is being processed. So, snapshot really does not contain data of an open file, only the changes that are coming to disk are written to snapshot, while the backup continues to run. So, size of backup is dependent upon the disk activity. I hope that clarifies!!
3. It is ideal to use AOFO to backup pst files to make sure you get a consistent backup.
4. There will be no corruption. MS recommends using VSS for backup of all files, and that really is the future. If you take a look at all OS after Windows 2003, they all have to use VSS, it is no more an optional thing.
So, use AOFO for file, folder backup without any issues. For database backups, though there are some known limitations of VSS, but nothing that can be called a data threat.
There are some more details for your reference in this article:
https://www-secure.symantec.com/connect/articles/advanced-open-file-option
Please mark it a solution, if this is useful.
Thanks
10-27-2009 09:38 AM
10-27-2009 09:46 AM
Answers follow:
1. Leave it automatic, BE will use VSS if it encounters a Windows 2003 or above OS, as per recommendation from MS. For OS older than Windows 2003, VSS will not be used. So, automatic should work for you.
2. When backup job starts, snapshot is taken, which is just an image of current disk layout. Then the backup starts, and BE takes the data directly from disk and if there is any change request coming to disk, it gets written to snapshot file, while BE continues to do the backup withouth noticing any disturbance because of disk activity. Once Backup is completed, the snapshot file is commited to disk and changes are written. So, rest of the file, of course is on the disk and backup job backs up that data from disk. For more information, i would suggest you to do some more reading on "Copy on Write" mechanism used by VSS.
Thanks
10-27-2009 10:19 AM
10-27-2009 10:47 AM