SQL Server has encountered 1 occurrence(s) of IO requests taking longer than 15 seconds to complete

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SQL Server has encountered 1 occurrence(s) of IO requests taking longer than 15 seconds to complete

Kumar-386306

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February 14, 2007 at 11:47 pm

#61102

Hi All,
I new to SQL Server support form and new to SQL Server. Today in my office, I got a call from the user saying the that the Application is very slow and giving some timed out error. When I was looking into the Server Error log, I found the below listed error message. SQL Server 2000, built with SP4
"SQL Server has encountered 1 occurrence(s) of IO requests taking longer than 15 seconds to complete on file [D:\MSSQL\MSSQL\data\tempdb.mdf] in database [tempdb] (2). The OS file handle is 0x000003B0. The offset of the latest long IO is: 0x000000b7dc4000"
After that I was keeping on searching for the error message over the net and in the discussion forms, I see most of the Guru's has said like it is some what the hard drive problem.
Kindly let me know, what are possible causes for this warning ? also let me know how I can confirm it's as Hard drive problem. ? And what is the fix for this issue. ?
Thanks in advance...

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Sugesh Kumar One Orange Chip Points: 27311 More actions · Answer 1

Did u check for any errors in the event viewer. Its hard disk problem only also check for the disk space in the drive. start to monitor the disk i/o.

Cheers,
Sugeshkumar Rajendran
SQL Server MVP
http://sugeshkr.blogspot.com

vkrist@fen.com SSC Enthusiast Points: 134 More actions · Answer 2

Check the min and max ram assigned to the SQL Server. Make the minimum less than the max and make sure you leave enough for the OS. You may need more on x64 than x32 (we did).

I struggled with this issue for weeks. I went through a whole bunch of things including getting faster RAM, tweaking raid policies, aliging drives etc but all I ended up having to do was lower the minimum ram for the SQL Server. Our SQL 2005 Standard x64 Edition Server on Windows 2003 x64 R1 had the minimum and maximum set to 15.3 GB. When I set the minimum to 8 GB, it seemed to allow SQL Server to be smart and hand back more RAM to the OS so the IO system would not choke when a 200 million row table was being reindexed. The server has a total of 16 GB of RAM and we set up our SQL 2000 servers with 700 MB of free RAM and never had problems with exactly the same reindexing job but it seems that SQL 2005 on Windows 2003 x64 R1 needs more RAM for the OS.

Vincent Krist

Kumar-386306 Default port Points: 1464 More actions · Answer 3

Hi Vincent,

Thank you for the details mail. As I am new in the SQL DBA Environment, I see that we need to assign some memory for the OS too, while configuring the SQL Server.

Let me provide the Production Server information.

RAM: 4.00 GB

When I look into the SQL Server Properties, I see that the it has configured as mentioned below:

Dynamically Configure SQL Server Memory

Minimum: 0MB - 4096 MB - configured as 0MB

Maximum: 0MB - 4096 MB - configured as 4096MB

Can you please tell me, whether I need to make any changes for this SQL Instance. Also FYI.. for past 5 days I dont see any IO Request in the Error Logs. Considering this, do I need to make any changes for this issue.

Please let me know.. Thanks in advance.

Best Regards

Senthil Kumar

Frances L SSCarpal Tunnel Points: 4727 More actions · Answer 4

Since I am new to SQL server DBA, too. If I understand well about this.

Check the min and max ram assigned to the SQL Server. Make the minimum less than the max and make sure you leave enough for the OS. You may need more on x64 than x32 (we did).

SenthilKumar configuration for Sql server Minimum: 0MB - 4096 MB - configured as 0MB is too small.

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 5

What this message means is that SQL issues an IO to windows and has not received a completion notification in 15 seconds.

A 15 sec delay on IOs is a very bad thing. It is usually a io bottleneck issue. It can also be caused by antivirus scanners (if they are configured to check every write to disk).

If you see this regularly do some throughput tests to your disk, make sure that you have acceptable IO performance. You can also use perfmon. Watch the sec/transfer, sec/read and sec/write counters under PhysicalDisk. They should be below 10ms

Check the windows event log, see if there were any errors logged at around the same time.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

Kumar-386306 Default port Points: 1464 More actions · Answer 6

Thank you to all for providing a valuable information. Let me check it out and get back to you...

Best Regards

Senthil Kumar.R

cflorescu Valued Member Points: 65 More actions · Answer 7

Hi Senthil, did you find a sollution for your problem? We are running into the same situation...

Carmen

Kumar-386306 Default port Points: 1464 More actions · Answer 8

Hi,

I dont see that problem now.. here is the below KB related to this problem.

http://support.microsoft.com/kb/897284

Regards

Kumar