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AskSQLTeam
Ask SQLTeam Question
0 Posts |
 Posted - 2002-01-15 : 14:36:41
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| philip writes "If you have 4 equally sized files in a filegroup and 4 CPUs on the server. When doing an insert of 100MB to the filegroup, will SQL allocate 4 IO threads writing 25MB to each file in parallel and each thread on a different CPU ?Or is it a single IO thread switching between the files ?Or is it 4 IO Threads but NOT concurrent ?" |
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JamesH
Posting Yak Master
149 Posts |
Posted - 2002-01-16 : 08:04:42
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| I would think that this would mainly depend on your NT machine's architecture. I doubt that sql would allocate 4 I/O threads in the manner you suggest unless each file is physically located on a different channel. My guess would be that SQL would try and write the data to cache (logical write) and would write to disk (physical write) when it needs the space (in cache) and the data has not been referenced for a while. I set up most of my large servers in this manner:c:\ - Raid 1 - 1 Channel: o/sd:\ - Raid 5 - 1 Channel: Datae:\ - Raid 5 - 1 Channel: DataL:\ - Raid 1 - 1 Channel: LogI also make sure that my databases (VLDB's) are split among D&E for data, and L for Log. Hope this helps. JamesH. |
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Filegroups and IO