Topic
3 replies Latest Post - ‏2013-10-20T20:59:09Z by bio1975
bio1975
bio1975
7 Posts
ACCEPTED ANSWER

Pinned topic V7000 or V3700 best configuration quorum and number of disk

‏2013-10-04T15:15:26Z |

Hello

I need buy a Storewize, i need help for select the number of disks (for data and quorum),  i have two problem:

- quorum :

for initial configuration i have only internal disks, for the quorum  i need use  dedicated hdisk ?  is possible use disks  used for storage pool data? (it is best use spare, candite or assigned disks?)

- number of disks

The magic number for disk on the storewize is 8 or multiple. is correct? i want make two raid 10 with 8 disk at 600 GB 10k is good idea? i need connect 3 host vmware esxi 5.1

thanks for the help

Fabio

  • AndersLorensen
    AndersLorensen
    139 Posts
    ACCEPTED ANSWER

    Re: V7000 or V3700 best configuration quorum and number of disk

    ‏2013-10-05T07:05:52Z  in response to bio1975

    In my experience, Raid5 for SAS disks is the best way to go. How many disks depends on how many TB and IOPS you need.

     

    You can do whatever configuration you like, but if performance and disk Space is your main concerns, I'd go with the following, based on your suggested config (two raid10 with 8 600GB 10k disks each gives around 4,8 TB usable Space and around 2300 IOPS)

    The same disks in a raid5 configuration gives 8,4 TB usable Space and around 2400 IOPS.

     

    Now IOPS is not just IOPS, as there is a big difference between random and sequential, and read and write. The raid10 is great at random writes, but bad at sequential writes, where the raid5 is the other way around. But for the average workload these days, Raid 5 is the way to go, unless you have unlimited funds!

     

    For a 3-host VMWare setup I normally go with 22 identical disks. This will make 3 raid5 of 7 disks, a hotspare, and the option to add 2 SSD disks later if performance is an issue. Add them all to the same pool and make some volumes for vmware from that pool.

    Also, if going with the v3700, go with the cache upgrade, its cheap and worth it.

     

    Not sure what you mean by a quorom disk. You dont need any dedicated quorom disk for the Storwize configuration. Quorom configuration is only really needed on SVC.

     

    --

    Anders

  • TMasteen
    TMasteen
    260 Posts
    ACCEPTED ANSWER

    Re: V7000 or V3700 best configuration quorum and number of disk

    ‏2013-10-05T17:27:15Z  in response to bio1975

    Fabio,

    In a V7000 system with a single control enclosure or without any external managed disks, quorum is automatically assigned to drives. In this scenario, manual configuration of the quorum disks is not required.

    Quorum configuration is chosen by the following criteria:

    • The drive is redundant and stable.
    • The drives are in a control enclosure.
    • No fatal errors have been logged against the drive
    • Quorum is distributed among the available control enclosures.
    • Solid-state drives (SSDs) are avoided.
    • Nearline hard disk drives are avoided.
    • Drive use in order of priority is spare, candidate, and then member.

    These criteria are not requirements. On configurations where meeting all the above criteria is not possible, quorum still is automatically configured.

    This and more about quorum can be found at: http://pic.dhe.ibm.com/infocenter/storwize/ic/index.jsp?topic=%2Fcom.ibm.storwize.v7000.641.doc%2Fsvc_scsiquorumdiskovr_1bchni.html

     

    • bio1975
      bio1975
      7 Posts
      ACCEPTED ANSWER

      Re: V7000 or V3700 best configuration quorum and number of disk

      ‏2013-10-20T20:59:09Z  in response to TMasteen

      Thank you for all info!

       

      By fabio