September 6, 2012 at 10:28 pm
Hi Experts,
Today one of my database took more than expected time for backup i have no idea why it took much time, can any one help me in this if any one gone through this condition/situation. your suggections could help me out in future.
The size of the backup is 30GB and the server is SQL Server 2005 enterprise edition on windows 2003 enterprise edition.
Thank you in advance
September 6, 2012 at 10:41 pm
How much longer did it take? Is the backup larger? Can you determine if there was other activity at the time of the backup?
Usually if a backup takes more time, it's more data or I/O issues.
September 6, 2012 at 11:10 pm
Hi Steve,
Thank you for your reply, usually it use to take 18 minutes but now it took more than 45 minutes and there is one job running at that time that was Backup of that database, I have not checked the I/O of the data at that time, and can we see that information now after completing the backup if so where can we find that.
Please let me know about this so that I can trace the things and can be aware of that for future.
Thank you in advance.
September 7, 2012 at 3:27 am
Backup is an IO bound operation. Either your DB has become significantly bigger (unlikely) or the source or destination drives for the backup are reading or writing slower. Check disk stats on both drives.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
September 11, 2012 at 11:27 pm
Hi,
Actually I am taking my backup from cmd window with a script it’s a general script to take a backup, but I am taking the backup file to a local drive/disk, as I do in general to a SAN drive/disk through maintenance plan. Will this cause any time variation in taking a backup to a local than to a SAN drive?
September 14, 2012 at 8:51 am
ksr39 (9/11/2012)
Hi,Actually I am taking my backup from cmd window with a script it’s a general script to take a backup, but I am taking the backup file to a local drive/disk, as I do in general to a SAN drive/disk through maintenance plan. Will this cause any time variation in taking a backup to a local than to a SAN drive?
Yes. Backing up across the network will absolutely be slower than backing up to a local drive.
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September 15, 2012 at 9:28 am
Hi Ksr,
First thing to do is explain your disk setup, so we can understand more about your system. You have already explained that the normally backups are written to a SAN drive, but now your backup is written to a local drive.
The information we need includes the following:
- Is it a physical server or a virtual server?
- On a physical server, how many local disks does your server have? How are they setup? (.e.g. raid levels, partitions, etc.)
- On a virtual server, how many other virtual servers share the same storage facility? (In most cases local disks of virtual servers are actually on a SAN drive.)
- How many other servers have a SAN drive on the same storage facility? (In most cases all these SAN drives share the same physical disks so they compete for performance which each other.)
- On a virtual server, is the SAN drive located on the same storage facility as the local disks?
- Which drives are magnetic rotating disks (e.g. normal hard drives) and which are Solid State Drives (SSD)? (SSD's have significantly better performance, but are a lot more expensive.)
For instance you may have a simple setup where you have a physical server with one local drive which contains the Windows operating system, SQL Server, and all your databases files. Backups are normally written to the SAN drive. In this case during a normal backup the database is read from the local disk and written to the SAN disk. However when you are performing a backup to the local disk the databases is read and written from the same drive which typically reduces performance significantly. For as I can see this compares best to your explanation but we can't be too sure.
If you can't answer those questions, you should probably speak with your storage administrator to get learn how the storage facilities are setup.
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