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zaty2405
Yak Posting Veteran
58 Posts |
 Posted - 2010-04-19 : 09:25:11
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| Hi,We have been getting the following error in our sql server log"SQL Server has encountered 1 occurrence(s) of IO requests taking longer than 15 seconds to complete on file [E:\prod\MSSQL\data\prods_9.ldf] in database [PROD] (7). The OS file handle is 0x00000418. The offset of the latest long IO is: "This caused the application to loose connection.May I know how to resolve this issue and how to check what actually caused this? Storage team said theres nothing wrong with the storage |
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GilaMonster
Master Smack Fu Yak Hacker
4507 Posts |
Posted - 2010-04-19 : 10:13:34
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| The message indicates slow performance from the storage subsystem. It's not an error, it's a warning. It's saying that SQL issued an IO request to the storage and that request was not completed 15 seconds later. Since IO operations are ideally supposed to take under 15ms, one over 15s is a concern.Ask the storage team to do some performance monitoring on their storage, what the utilisation and latency looks like.--Gail ShawSQL Server MVP |
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zaty2405
Yak Posting Veteran
58 Posts |
Posted - 2010-04-19 : 10:34:20
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| Thanks Gail.The problem is whenever this message appear in the sql log, the application also get disconnected.I already check with storage side and according to them theres no issue on their side. Now everyone is pointing to DBA saying its database issue.Is there any other area that I should be looking at?Thanks |
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GilaMonster
Master Smack Fu Yak Hacker
4507 Posts |
Posted - 2010-04-19 : 11:30:27
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| This message will not disconnect an application. A timeout might, otherwise it's a different problem.No other areas. This is blatently and obviously an IO performance problem. An IO request should not ever take 15 seconds when the recommended is under 15 ms. You can use perfmon to get an idea what the IO performance is like from the server, start with avg sec/read and avg sec/write, but at the end of the day, the cause of this message is slow IO performance. It's not a database issue. It's the database complaining that it's IO requests are taking forever.--Gail ShawSQL Server MVP |
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tkizer
Almighty SQL Goddess
38200 Posts |
Posted - 2010-04-19 : 13:27:05
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| Your storage team is incorrect if they say that the issue is on the database side. Not that Gail needs any help answering this, but I have a bit of experience with that error as many of my high rate of transactions were facing this issue a while back. On most of my systems we eliminated the warning by updating all drivers and firmware for the I/O subsystem. This is all done on the server side by a Windows admin. On the systems that still faced this slow I/O after these updates, we worked with out SAN team to optimize the system.Tara KizerMicrosoft MVP for Windows Server System - SQL Serverhttp://weblogs.sqlteam.com/tarad/Subscribe to my blog |
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zaty2405
Yak Posting Veteran
58 Posts |
Posted - 2010-04-19 : 20:40:21
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| Thanks Tara and Gail for your reply.We will work out with the storage team on this. |
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I/O Error