April 6, 2013 at 9:12 am
I have a 55 Gig database, and the differential backup for yesterday was 32 Gig !! It was about 5 gig the day before
So, I assumed I could look at my transaction log backups and find a huge T-log backup to identify what time of day something big happened. But my t-logs, every 15 minutes, show 1 backup > 1 gig, and all the others quite small, and similar to other days this week.
What can make a huge Diff backup, without generating huge t-log backup(s) ?
April 6, 2013 at 12:09 pm
differential backups contain all the extents that have been touched by updates, therefore a single row update would lead to 64k worth of backup. Educated guess some process or processes occurred that touched a lot of extents leading to a large differential backup but not necessarily a large log backup.
sounds like its time to reset the differential base.
---------------------------------------------------------------------
April 6, 2013 at 1:05 pm
The next Full backup is tomorrow morning, so that is good. Puzzled by the huge Diff though. I have trace files from that time period. Not sure the best columns to look at .... I/O ?, but maybe I'll take a look.
April 7, 2013 at 8:28 am
homebrew01 (4/6/2013)
I have a 55 Gig database, and the differential backup for yesterday was 32 Gig !! It was about 5 gig the day beforeSo, I assumed I could look at my transaction log backups and find a huge T-log backup to identify what time of day something big happened. But my t-logs, every 15 minutes, show 1 backup > 1 gig, and all the others quite small, and similar to other days this week.
What can make a huge Diff backup, without generating huge t-log backup(s) ?
T-Log backups that occur every 15 minutes happen 96 times a day. If you divide 32 by 96, the average T-Log size is only 0.3333.
--Jeff Moden
Change is inevitable... Change for the better is not.
Viewing 4 posts - 1 through 3 (of 3 total)
You must be logged in to reply to this topic. Login to reply