Topic
5 replies Latest Post - ‏2013-03-20T06:41:42Z by Padde
SystemAdmin
SystemAdmin
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Pinned topic DS3524 Array Config

‏2013-03-19T03:00:07Z |
Hey there.. I am picking up a dual controller DS3524 as our new 8GB FC SAN. The first 16 ports will be 900GB 10k SAS and the last 8 ports 600GB 10k SAS. I will be creating logical drives for use with a five node Server 2012 Hyper-V cluster.

My questions are:

1. What controller "owns" which drives? Or are controllers active\passive only?
2. How would you recommend I setup the arrays.. i.e. which RAID levels with what drives?

I am leaning toward RAID5 as I am hosting a variety of differnt types of VMs (File, Web, SQL, DCs, VDI, etc). Our current DS4000 2GB IBM SAN is all RAID5. Several logical drives adding up to about 15TB of which only 9TB is used)

Thanks!
Updated on 2013-03-20T06:41:42Z at 2013-03-20T06:41:42Z by Padde
  • sdenham
    sdenham
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    Re: DS3524 Array Config

    ‏2013-03-19T03:10:00Z  in response to SystemAdmin
    1) You define which controller "owns" each array when you define it. This becomes the preferred path for the LUNs within that controller. Depending on the host type and the firmware level, you may have borh RDAC mode and ALUA mode available. From the perspective of any single array, the controllers are active/passive (in RDAC mode) or preferred/alternate (in ALUA mode). Best performance is ALWAYS through the "owning" path. With RDAC, an attempt to access the drive through the other path is rejected; with ALUA it is shipped to the other controller to handle. But from the perspective of the system, it is active/active - one controller owning (typically) half the arrays and the other controller owning the rest, both controllers active for their owned arrays and passive backup for the other controllers' arrays.

    2) RAID 5 is probably a good choice unless your data is extremely critical. With this size drives and the "better" 10K drives, the odds of a second disk failure while rebuild is going on is quite low. With large 7200 RPM NL-SAS drives, RAID 6 is usually the safer choice. RAID 1 is a good choice for small arrays where the RAID overhead would be large for 5 or 6.
    • SystemAdmin
      SystemAdmin
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      Re: DS3524 Array Config

      ‏2013-03-19T15:49:35Z  in response to sdenham
      Thanks, that helps.. I see each controller has four FC ports.. Is there really any need to use more than two (one to each FC switch)? And does it matter which ports I use?
      • SystemAdmin
        SystemAdmin
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        Re: DS3524 Array Config

        ‏2013-03-19T15:56:35Z  in response to SystemAdmin
        Here is how I was thinking of setting up the arrays

        Fast Write LUN1 - 4 x 600G Controller A Pref, RAID10
        Fast Write LUN2 - 4 x 600G Controller B Pref, RAID10
        Fast Read LUN1 - 8 x 900G Controller A Pref, RAID5
        Fast Read LUN2 - 8 x 900G Controller B Pref, RAID5
      • Padde
        Padde
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        Re: DS3524 Array Config

        ‏2013-03-20T06:38:40Z  in response to SystemAdmin
        If you have two san-switches for redundancy you connect each controller to both san-switches.
        • Padde
          Padde
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          Re: DS3524 Array Config

          ‏2013-03-20T06:41:42Z  in response to Padde
          sry, didn't read the question carefull enough...and can't edit my reply.