SQL Server Performance Forum – Threads Archive

SQL Server and SAN

We have a client that is having intermittent performance issues. The data files are located on a SAN but the SAN is also being used by an imaging system. What needs to be done to make sure that there are no performance hits from the imaging system? Can the disks on the SAN be segregated in a way that will alleviate any I/O degradation? Thanks for any input, I am not very familiar on how to set up SANs. Daniel Reber
Datamasters, Inc

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the physical disks must be dedicated to the database.
The typical SAN configuration has phyical disks formed into RAID Groups, each RAID Group is then carved into LUNs allocated to applications as necessary, for a performance critical database, it is essential that the RAID Group is allocated to a single LUN dedicated to the database.
of course, separate RAID Groups for data, log and possibly tempdb. if the Imaging system makes heavy use of disks, the database should be moved to a separate SAN if it is very important

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Thanks for you insight. Daniel Reber
Datamasters, Inc

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This a good article which may solve your question
http://www.sql-server-performance.com/ew_san.asp

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You might want to look at a couple things on the SAN. 1. Follow Joe’s solution with dedicated disk. That’s critical on a high IO database environment, regardless of what some of the "SAN Experts" tell you. 2. You might want to consider having only the production database environment with one of the storage processors as the primary processor. The idea is usually to load balance between the processors evenly; however, it’s something to consider. Have you looked at the overall performance of the SAN? What are your disk queue lengths when this happens? MeanOldDBA
[email protected] When life gives you a lemon, fire the DBA.

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