7 Replies Latest reply on Oct 1, 2009 5:59 AM by Texiwill

    VMFS vs. Physical Disk performance

    zenomorph Hot Shot

       

      I've read alot about the performance of VMFS in comparison to RDM and physical disk comparison.

       

       

      However what I find is alot of the times when if the comparison is done for eg. dBase performance it usually based on using eg. a SAN with native Physical Win2k3 machine running SQL and then ESX with VMFS running Win2k3 and SQL. Most of the times when they comapare I find they configure the physical servers local disks for optimum usage that is on the physical machine they may mirror the logs and RAID5 the dbase partition etc. and for the camparing VM, theVMFS volume they will do the same similarly define the SAN with mirror lun for the Logs VMDK disk and then the database RAID5 luns.

       

       

       

      The reason I'm asking is because we will  be setting up an EMC Clariion SAN and running some of our SQL servers which use local storage and by standard we just RAID5 the disks and place the logs and database on seperate partitions or sometimes follow the best practice of mirror log volume and RAID5 the database volume.

       

       

      But on the Clariion CX-3 we will be just defining standard RAID5 groups for the VMFS volumes. All systems will just use RAID5 luns rather than having seperate RAID1 LUNs and some RAID5 luns just for easier maagement. I understand that for a start comparing the local SAS 300GB 15K disks on HP DL580 with the EMC 300GB 15K FC disks the performance is quite signiticant compared to local. But by the time we RAID5 VMFS volumes with the FC disks what I haven't seen is how much performance difference there really is betwen running the local disk performance and SAN disks.

       

       

      The thing I'm trying to get at is will be challeged the question whether running the EMC Clariion with RAID5 VMFS performance compared with local, native SAN physical host performance and the RAID5 VMFS performance on the SQL server.

       

       

       

       

       

      Many thanks

       

       

      Cheers