SQL Server Performance Forum – Threads Archive

What is doing so many disk writes?

Am using sql 2000 sp3a on windows 2003 server. Using perfmon, it seems that the DB is constantly waiting on disk writes (Always doing about 7MBytes writes/sec) and it’s the sqlsvr process which is responsible for the writes. Using profiler, I didn’t see anything with a large number of writes (If anything, I see a lot of reads, but Disk reads/sec are low). How can I determine what is responsible for all the disk writes?

See if you have checkpoints going on during this. Do the drives this is happening on help you at all? Is it happening on the drive with the tempdb vs. the log files vs. the data files? MeanOldDBA
[email protected] When life gives you a lemon, fire the DBA.

Is the user database is in SIMPLE recovery model. Satya SKJ
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The database is in simple recovery mode.
I don’t know abuot checkpoints, but I changed the recovery interval to 15 minutes. I’ll see if it helps. Unfortunately, my system has one logical drive, so I can’t get much info from that.
But how can I tell which operations do all this writing?

There are three areas of data collection to troubleshoot disk I/O bottlenecks. The first is System Monitor#%92s Physical Disk object. System Monitor should capture all counters and all instances prior, during, and after the slow performance periods, if possible. In the System Monitor (PERFMON) there are five Physical Disk counters for each physical disk contained in the Logical Drive that are key to identifying I/O bottleneck:
Avg. Disk Queue Length
Avg. Disk sec/Read
Avg. Disk sec/Write
Disk Reads/sec
Disk Writes/sec Satya SKJ
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