September 5, 2011 at 3:18 am
I have just been looking at the duration of the backup, and what suprises me is how long the backup takes to run, I found that using symantec netbackup the duration of the backup was almost as much as doing a full backup as well. I was really quite suprised, I am looking out for ways in which I can reduce this, I noticed that the SQL service is local system account which isnt best practice, but I'm assuming that with the SQL service set to local system account, and the file initialisation permissions set to administrators, will this cover the local system account for the SQL service as well.
Full backup takes: 137 mins
Differential takes: 133 - 135 minutes
I look forward to hearing other replies.
September 5, 2011 at 7:58 am
Backups are largely an I/O operation. How fast are your disks? Are you backing up over the network? Are there contentions on the system? Can you put multiple disks to work on the problem? Just how much data are you backing up? The more data you move, the longer it takes.
Hard to know what the issue might be without more information.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
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September 5, 2011 at 8:08 am
Are you saying that a Differential backup done using just the standard TSQL commands is quicker?
If the database has been heavily updated since the previous full backup, a differential can take almost as long as a full backup.
For the backup times posted, how big is the full backup vs the differential backup?
September 5, 2011 at 8:56 am
The size is around 200GB for both differential and full.
September 5, 2011 at 11:57 am
Dean Jones-454305 (9/5/2011)
The size is around 200GB for both differential and full.
Which is why the differential is taking as long as a full backup
The differential should only be backing up the pages that have changed since the last full backup, so...
either your database is heavily updated, resulting in almost every page changing between the full and differential backups
or
you aren't actually running a differential at all.
September 7, 2011 at 1:39 am
Hey, I totally agree with Ian Scarlett.
If your files change alot. I recommend you use incremental backup instead of deferential backup.
Recheck your backup task, see if it did deferential backup not full backup.
September 7, 2011 at 3:23 am
106919046 (9/7/2011)
Hey, I totally agree with Ian Scarlett.If your files change alot. I recommend you use incremental backup instead of deferential backup.
Recheck your backup task, see if it did deferential backup not full backup.
SQL Server doesn't support the concept of an incremental backup, only differentials. If the differential backup is near to the size of the full, then you're essentially doing another full backup. I'd suggest adjusting your schedule so that you do slightly more frequent full backups and then the differential will be more meaningful and faster.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning
October 12, 2011 at 9:38 am
Dean Jones-454305 (9/5/2011)
The size is around 200GB for both differential and full.
i've seen that. chances are its something in your schema that causes too many extents to change with data modification and/or maintenance running every day
October 23, 2011 at 10:32 pm
The chances are very few that your Full & differential backups sizes will be same.
because differential backup backs up only the changes that have taken place since last full backup.
When is full & differential backup scheduled.
Is full backup scheduled Daily or weekly & when does differential occurs i.e daily or after interval of few hours
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