Backup of 190 GB databases taking 6.5 hours

Last Post 25 Jan 2011 12:30 AM by ctseah. 10 Replies.
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ctseah
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13 Jan 2011 01:28 AM
Hi,

We are using Arcserve to backup our SQL 2008 databases to tape.

The system databases and the user database totalled up to be 190GB, and a full database backup of these databases using Arcserve is taking 6.5 hours.  On some day it may take as much as 10 hours !

One of the user database has a datafile mdf as big as 172 GB.

Is it normal to take so long ?

Please advise what could be causing this long backup duration.

Thanks in advance.
rm
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13 Jan 2011 04:58 AM
Will not take that long in sql2k8 to backup to disk with compression, but don't know Arcserve enough. Did you check with CA?
russellb
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13 Jan 2011 05:07 AM
You should backup to disk, then tape off the .bak files.
ctseah
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13 Jan 2011 04:27 PM
Client wants to use the enterprise backup software such as Arcserve to backup the production databases as the Arcserve sql backup agent was also purchased.

But any suggestion in troubleshooting this ? At least I need to ensure that it is not due to my sql databases causing the long backup duration.

Thanks in advance.
russellb
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14 Jan 2011 03:55 AM
So you're backing up the entire server, and directly to tape? That is the worst possible way you can do it, and you should explain that to the client. Is it a VM? If they want to back up entire machines or VMs, that's great, but not for the data drives of SQL Servers.

It probably IS the databases causing the long duration...other than the fact that the backup is going straight to tape...

Is the backup deduping too? I've never used Arcserve, but I bet that takes some time too.
russellb
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14 Jan 2011 03:57 AM
One more thing...how is the tape device connected? Over the LAN? What speed?  By the way, one of my backups -- 108 GB took 29 minutes last night.  With just native SQL Backup, backing up over the LAN (1Gb) to a NAS.  Point is, I'm backing up over the wire and to a NAS -- which is a pretty slow way to do it, but it is FAR faster than backing up to a tape device.

Later, the .bak files will get taped off.
gunneyk
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16 Jan 2011 07:17 AM
That is a horrible backup time but I highly doubt it has anything to do with SQL Server itself. The time to take a FULL backup is almost directly related to the hardware especially the disks the database reside on and the finalk backup destination. I suspect your tape device is just plain dog slow.
ctseah
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18 Jan 2011 10:38 PM
Hi,

I scheduled and ran a SQL native backup to disk, it was fast enough; a 47 GB of database was completed in just about 8 mins.
I have not checked whether compression was turn on at server level as default setting was used. However the size of the .bak is the same as the .mdf file.
Does that suggest that compression was probably not turned on ?
Will compression increase or decrease the backup time if I use SQL native backup to disk ?

thanks in advance
rm
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19 Jan 2011 06:09 AM
Doesn't sound compression was on in your test, backup with compression is faster.
gunneyk
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19 Jan 2011 06:12 AM
If compression is turned on and assuming the data is compressable (which most is) then the backup size will be less than the amount of actual data in the MDF. How much depends but a 60% reduction is not uncommon so I would say you did not specify backup compression. Usually backup compression decreases the time to backup and restore by reducing the amount of I/O that occurs since a smaller amount is written to disk. But it does take more CPU resources than a regular backup. So if you are already CPU bound then compression may not be much faster. But as always it depends .
ctseah
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25 Jan 2011 12:30 AM
Hi,

Thanks for all your help and sharing.

regards


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