SQL performance on SAN

  • jmatt

    SSC Enthusiast

    Points: 194

    We recently installed a EMC FC4500, and are running SQL2000(ent)on the SAN. We have noticed that the performance on SQL processes is slower (about afactor of6) on the SAN than on the original local RAID.

    We have noticed that when running the process on the DB that is on the SAN, the number of reads in the process goes up about

    a factor of 6.

    Anyone ever run into this? We have noticed increases in other SAN functions (backups, and SQL backups) it is just when it runs this process runs. Kind of banging our heads

    right now as to if it is a SQL issue or a SAN issue.

    Thanks for any info.

  • Brian Knight

    One Orange Chip

    Points: 27249

    He recently installed a Hitachi SAN and experienced the same problem. It wound up being the SAN's fault but it took a number of weeks to prove it. There was quite a bit of configuration that had to be done before the SAN performed better than the SCSI drives. Are you running multiple cards going to the SAN?

    Brian Knight

    bknight@sqlservercentral.com

    http://www.sqlservercentral.com/columnists/bknight

  • jmatt

    SSC Enthusiast

    Points: 194

    Yes..there are 2 HBA cards going to the SAN.

    They are strictly for failover, there is no "teaming" at this point.

    Do you know what kind of "tuning" had to be done on the SAN?

  • Wesley Brown

    SSChampion

    Points: 12035

    There is no "quick" tuneing for a EMC SAN. There are ways you can spread out the data among several spindles to increase performance. I would talk to your local EMC rep and tell them you are having heavy IO and poor performance from the san. It took us weeks to get them to come out and tune the san to meet or DB needs as well.

    Wes

    http://www.sqlserverio.com
    http://www.cactuss.org
    http://www.salssa.org

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