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Gyto
Posting Yak Master
144 Posts |
 Posted - 2009-07-09 : 07:00:53
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| Hi there,Our SQL Server cluster is currently reporting a high "Average Disk Queue length" in SQL Server Performance Monitor. It hasn't been a problem before and as far as I'm aware there is no reason why there should be any extra load on the server. The CPU and memory usage are still normal. Are there any common causes for this?Is there an easy way to see which processes/databases are contributing to this?Thanks,Matt |
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tripodal
Constraint Violating Yak Guru
259 Posts |
Posted - 2009-07-09 : 15:47:56
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| Depending on your Os you have several options, the easies is The Resource Monitor in server 2008.You can use task manager to add columns for read / write bytes. And look at what services are activly reading / writing data.Depending on your disk setup, you could have a failing drive causing your array impacted performance.Also all of the obvious disk users, Backups, Virus scans, Defragmenters will do this quite easily. |
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sodeep
Master Smack Fu Yak Hacker
7174 Posts |
Posted - 2009-07-09 : 23:13:37
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| Are your Backups and Log file stored in same drive? Eloborate more about your scenerios so we can help. |
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Gyto
Posting Yak Master
144 Posts |
Posted - 2009-07-10 : 04:52:00
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| Hi there,Sorry...not enough info...we are running windows 2000 on a SQL Server cluster. Our data and logs are mostly on seperate drives. Our disk setup is RAID 5 using, I believe, at least 3 disks for data and 2 for logs from our SAN, so I don't think a disk going down should affect it too much as one of the reserve disks should cut in to replace it.In task manager sqlservr.exe is easily highest in the I/O reads and writes (bytes) fields. Is there an easy way in SQL Server to query which of the databases is producing the majority of the I/O traffic?Thanks |
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RickD
Slow But Sure Yak Herding Master
3608 Posts |
Posted - 2009-07-10 : 05:26:31
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| Do you have a virus scanner scanning you .mdf/.ldf files? If so, you need to add an exclusion. |
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Gyto
Posting Yak Master
144 Posts |
Posted - 2009-07-10 : 11:24:55
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| Nope, we don't have any virus scans running on our SQL Servers throughout the day.... =S |
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tripodal
Constraint Violating Yak Guru
259 Posts |
Posted - 2009-07-10 : 15:25:00
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| There are a bunch of performance monitor counters you might be able to make use of.In my case It was always obvious which database was causing the usage.Using enterprise manager for sql 2008 you can right click your server and hit "Activity monitor" It can sort by activity per database. |
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High 'disk queue length' in performance monitor