February 21, 2011 at 11:26 pm
Dear Members,
Good Morning. We are having an issue in recent days in SQL Server 2005 while fetching data from drive. We are encountering the following Issue from Database Servers and the Error is logged like :
Message
SQL Server has encountered 7 occurrence(s) of I/O requests taking longer than 15 seconds to complete on file [XXXX.mdf] in database [YY] (6). The OS file handle is 0x000007CC. The offset of the latest long I/O is: 0x000006c6648000 .
To resolve the issue we are moving the Data files from one drive to another drive and after that we are formatting the SAN Drive. Can someone help me how to resolve this issue.
Regards,Thulasi.
February 22, 2011 at 5:53 pm
SQL Server is telling you that there is a problem somewhere in the I/O stack. Start with the I/O DMV's and also watch the server physical disks using windows perfmon.
February 22, 2011 at 8:26 pm
Is it occurring consistently or sporadically? If consistently then there is probably something seriously wrong with the SAN, either in the communication layer or the controller and possibly at the disk level. If sporadically then it may be due to excessive activity and by excessive I mean that it is more than the configuration can support and you need to improve your IO throughput.
David
@SQLTentmaker“He is no fool who gives what he cannot keep to gain that which he cannot lose” - Jim Elliot
February 22, 2011 at 10:13 pm
Dear David/Craig,
Thanks for your inputs. Yes we are having huge Data in the Drives and observed that load on Physical is is high. after that i have moved some physical data files to another Drives. Initially it's occurring rarely after that it's occurring continuously. Seems there is also an issue with SAN as you said. Because we are using the SAN in Drive in different DB Server. Recently the issue is occurring Server by Server. Can you suggest which configuration is suitable.
Regards,
Thulasi.
February 23, 2011 at 6:10 am
So, it sounds like you are sharing physical san disks between 2 or more database servers. It is a possibility that there is contention on the drives there but in order to determine that, you need to engage your SAN administrator and look at the IO patterns from the SAN controller perspective to determine where the bottleneck is.
February 23, 2011 at 6:31 am
Hi Craig Thanks for the inputs Yes , we have SAN and each V Disks is created to assign in each Server. I am in the process of getteing the required information from Storage team. Will Update you once i receive the info.
Thanks once again..
February 23, 2011 at 12:46 pm
There are at least a dozen things that can be done suboptimally or just plain wrong when you have SQL Server files on SAN storage. If you are talking virtualization on SANs then double that number. I have yet to see a client do even half of the things right. I strongly urge you to get a qualified professional in place to evaluate your setup and configuration and help you get where you need to be.
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service
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