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evilDBA
Posting Yak Master
155 Posts |
 Posted - 2007-11-08 : 06:52:06
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| Again one client with SAN EMC and again performace is several times worse then you can have with a cheap and primitive IDE drive... :(Anyway, my question. I am monitoring many parameters, including Avg Read Queue and Avg Write Queue.So if I ReadQueue=3 and WriteQueue=7, what does it mean?Scenario 1, there are 2 different Queues (R- read request, W - write request):Windows --> DeviceRead. Queue: R:R:RWrite Queue: W:W:W:W:W:W:WScenario 2:Windows --> DeviceCommon Queue: W.R.W.W.R.W.W.R.W.WIn other words, if SQL server flushes writes (TRAN COMMIT or CHECKPOINT), generating hundreds or even thousands of write requests in few milliseconds, so Queue grows to 100-300 for a second or so, are read requests locked during that time? |
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tkizer
Almighty SQL Goddess
38200 Posts |
Posted - 2007-11-08 : 12:54:14
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| You have to perform calculations on those values based upon your disk configuration. See my latest blog for an article about checking performance in SQL Server 2005. It goes into great detail on I/O issues.Tara KizerMicrosoft MVP for Windows Server System - SQL Serverhttp://weblogs.sqlteam.com/tarad/ |
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Avg Disk Queue values