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I have to re-occuring errors on SQL Server 2005 running on a virtual machine. The more pressing error is the "SQL Server has encountered 1 occurrence(s) of I/O requests taking longer than 15 seconds to complete on file" [Typically different file each time].

I also have a CPU not synchronized error and have read that IO errors can be caused by a "CPU Drift". I am not sure what a CPU drift is exactly and wondering if - this error is what is actually causing the I/O error to occur. Thanks you!

(Second error) "The time stamp counter of CPU on scheduler id 1 is not synchronized with other CPUs."

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Any danger of a specific question in there? –  Chopper3 Aug 2 '11 at 15:22
    
Unfortunately I lost the link I was thinking of that mentioned relationship between CPU drift and I/O errors. I was hoping for an easy fix. Looks like that's not the case, thanks gbn. –  Dina Aug 2 '11 at 16:02
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2 Answers 2

Well - the errors may be related. Are you using an AMD multi-core CPU? MS-SQL has problems with the independent CPU-timers. This can be fixed by applying MS-SQL 2005 SP3 or SP4.

The timer problem also leads to incorrect time measurements - so MS-SQL may indicate long times where the real execution takes much shorter time.

You can also search MS-Technet for this problem it is described there as well.

BTW - The Microsoft OS might suffer from the same problems. Do a ping to a nearby server. If you get negative or extraordinary high ping-times, you need to set a different timing mechanism in the boot.ini. But this does not fix the MS-SQL bug, since MS-SQL does not use an OS-call to determine the time.

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thanks! No, using Intel, not AMD. –  Dina Aug 2 '11 at 20:40
    
Interesting. I wonder what is causing that there. But SP3/4 will propably fix that, too. –  Nils Aug 3 '11 at 19:02
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Unrelated error messsages...

The IO error is caused by slow IO. Of course.

You have a virtual machine that is not providing enough IP bandwidth and resource to the host OS running SQL Server. See your sysadmins.

For the CPU one, I assume you didn't search Google to find this: http://blogs.msdn.com/b/psssql/archive/2006/11/27/sql-server-2005-sp2-will-introduce-new-messages-to-the-error-log-related-to-timing-activities.aspx

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Actually using SQL 2005 (not SP2) - which may not be reporting drift vs synchronisation errors separately. Will continue to search, but thanks for this! –  Dina Aug 2 '11 at 20:37
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