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SQLexcitesMe
Starting Member
3 Posts |
 Posted - 2008-05-16 : 04:27:08
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| I have a poorly performing SQL box. I have run perfmon and the avg read queue length is pretty much permanently maxed out at 100%.I have run a database index defrag.On further inspection the file system is highly fragmented. There is a file fragmentation of 98% with the mdf file fragmented in 25,000 pieces. Running a standard windows defrag does not resolve this.Two questions?1- Is heavy file fragmentation of the MDF file a likely cause of the read queue length bottlneck?2 - Why is the MDF file not defragmenting? Does the SQL server have to be taken offline? Is it possible to defrag a MDF file? |
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mcrowley
Aged Yak Warrior
771 Posts |
Posted - 2008-05-16 : 11:17:34
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| 1) It can2) Most likely because the file is open. try shutting down SQL Server, then defragmenting the filesystem. |
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tosscrosby
Aged Yak Warrior
676 Posts |
Posted - 2008-05-16 : 14:32:11
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| I've done this before and it should help, simply defrag the disk(s) that the mdf (and ldf??) is on, after shutting down the SQL services, as stated. I'd take a full database backup before attempting. Even though I never had any issues doing this, it's better safe than sorry.Terry |
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File Fragmentation and Disk Read Queue