After posting on a Symantec forum for help with Backup exec, I changed our backups from full(friday night-over weekend), differentials every weekday (using archive bit), to using the USN journal, modified time. It's still not backing up successfully and the differentials look as if they are trying to do a full backup!
The Full backup has a a few errors I'm trying to resolve(missing files, snapshots etc), but > 99% is backed up(2.7 T byte).
the original post on the Symantec connect forum :-


A little stage setting first:-

we have Backup exec 2010 R3, running on our backup server (MS Windows server 2008 32bit, 2 intel 3.06Ghz Xeon processors, 2G ram), Full backups transfer rate varies between typically 450-1,800MB/min, to a ESATA connected WD My Book Essential (wdbacw0030hbk-01 3TByte drive).

Unfortunately due to the length of time backups take(full backup off all our servers takes all weekend!), we've elected to do differential backups every weekday overnight.

The BIG problem is the differential backup of our main fileserver is very slow 20-50MB/min. I've had a look at the backup logs and one obvious issue seems to be the very large numbers of folders its backing up, for example:-

Byte count : 12,697,968,916
bytesRate : 31.00 MB/Min
Files : 116,528
Directories : 1,326,746
Skipped files : 0
Corrupt files : 0
Files in use : 0

Q.How come the directory count is way higher than the file count?

Any insight into the issue would be great,
Thank you!
>>End of Symantec posting.
At first I thought Sophos anti-virus scheduled AV scans were changing the USN journal modified time so after reading a Sophos article ( search for 43898 USN Change Journal And Sophos), I changed a few registry values and though I might be in with a chance.
No such luck, Mondays differential is still taking till Wednesday to complete!

Has anyone come across similar issues? and know of any workarounds?

Many thanks for any input!