SQL Server Performance

SAN recommendations

Discussion in 'Performance Tuning for Hardware Configurations' started by nosurfdj, Jul 31, 2006.

  1. nosurfdj New Member

    I need help in determining the best route to go with purchasing 2 new database servers running on a SAN or DAS.
    Currently, we have 2 DL570 first generation servers that each have their own HP MSA30. I've been reading up on SAN configurations to optimize performance, and I'm not sure where to go. I've read that it's best to have a large amount of disks of a smaller capacity with high RPM; I've also read that some people think that a DAS would be better than a SAN.
    So I'm debating between 2 configs:
    1.
    I'm looking at the MSA1000 enclosures because you can expand to up to three of these for a max of 52 disks. The only problem is with the cache-the MSA 1000 can only be upgraded to 512MB cache per controller. One article I read the guy wrote that if possible you should have as much cache on the SAN controller as the size of your database. Our database is 45GB, and it's highly unlikely that we'd be able to spend enough to get this much cache.
    2.
    On the other hand, going with a SAN solution is much more expensive, but I understand that there are alot of benefits. We don't currently have a SAN, so I almost think that going with the MSA1000 would be the best option for now, but the cache limitation of the MSA1000 worries me.

    Our database runs a hospital information system. We currently have ~100 users during the day. In the next year, we are adding bedside charting, physician order entry, and eventually going to an EMR. I'd estimate that we would have 150-200 user connections during the day after these installations.

    Any thoughts/suggestions?
  2. joechang New Member

    cache on a san is irrelevent,
    your system memory is the data cache, there is not likely to be anything in the san cache that is not already in system memory

    i am not aware of any important advantages of a san,
    considering that with extra brute force possible with da
    part of this is because most sans are built on obsolete systems,
    its like paying $20K for a server that normally costs $6K

    san generally have very poor sequential performance, so a table scan could saturate the san

  3. nosurfdj New Member

    Thanks for the input Joe. I think I'll probably look at going with the MSA1000 enclosures then.

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