3 Replies Latest reply: Jun 14, 2013 11:06 AM by Cindys-Oracle RSS

    zpool more than 80% but ZFS SAN storage is still lower than 80% will it affect performance?

    984266

      HI All,

       

      As we know, in ZFS, it is recommended to keep the disk usage below 80% to ensure the performance.

       

      However, the following is my scenario:

       

      I have a ZFS storage, which share by multiple servers, and overall Usage is lower than 80%.

       

      Server A has multiple  Lun (spool) from this storage, For example:

      - LUNPOOL/A

      - LUNPOOL/B

      - LUNPOOL/C

       

      Currently, LUNPOOL/B of server A is more than 80%, it reach 88%.

      Since the overall storage there still lower than 80 %,  will the performance for this LUNPOOL/B be affected?

        • 1. Re: zpool more than 80% but ZFS SAN storage is still lower than 80% will it affect performance?
          Cindys-Oracle

          Hi--

           

          What we recommend is that overall pool capacity should remain below 80% for best performance.

           

          Actually for all Solaris 11 releases and starting at the Solaris 10 1/13 release, pool capacity can reach 90% before

          performance is impacted.

           

          I'm not quiet sure I'm following this configuration so please it to me:

          1. Server A runs Solaris 10 and has a LUNPOOL exported from a ZFSSA?

          2. LUNPOOL/A, B, C, are all file systems? If so, do they quotas set? Otherwise, all file systems consume all pool space so I don't see how LUNPOOL/B of server A could reach 88% unless it has a quota.

          3. I wonder if A, B, and C are not file systems but volumes?

           

          Consider that the 80 or 90% is a pool capacity recommendation, not an individual storage recommendation, but maybe I misunderstand.

           

          Thanks, Cindy

          • 2. Re: zpool more than 80% but ZFS SAN storage is still lower than 80% will it affect performance?
            984266

            HI Cindy,

             

            In the zfs storage:

            it has:

            LUNPOOL/A

            LUNPOOL/B

            LUNPOOL/C

            LUNPOOL/D

            SERVERB/1

            SERVERB/2

            SERVERB/3

            SERVERB/4

             

             

            LUNPOOL present it to server A

            SERVERB present it to server B

             

             

            Usage on this zfs storage is 72.3% of 15T

             

             

            #

            root@ServerA # zpool list

            NAME         SIZE  ALLOC   FREE    CAP  HEALTH  ALTROOT

            A           99.5G  26.3G  73.2G    26%  ONLINE  -

            B            992G  59.9G   932G     6%  ONLINE  -

            C            1.94T  1.75T   191G    90%  ONLINE  -

            D            199G  4.29G   195G     2%  ONLINE  -

            rpool        278G  80.7G   197G    29%  ONLINE  -

            root@ServerA #

             

            as you can see the zpool "C"  in the zpool list output reported by Solaris 10 has reach 90%

             

            So do you think it has a performance issues?

             

            Thanks,

            Vincent

            • 3. Re: zpool more than 80% but ZFS SAN storage is still lower than 80% will it affect performance?
              Cindys-Oracle

              Hi Vincent,

               

              Thanks for the zpool status output, which cleared up all my questions.

               

              I see that pool C is at 90% and you are asking about performance. I think you are going to have to tell us if the performance has suffered since reaching 90%.

               

              Our current guideline for Solaris 10 1/13 releases, is keeping pool capacity at 90%. If the workload is mostly static, read-only, then you can increase this pool capacity limit to 95%. Whether a pool has a performance issue at 90% is also related to the workload.If you don't have a pool performance problem at 90% because the pool performs well or as expected, then you're fine for now. If the pool performance is sluggish as it reached 90%, then see if you can archive some data to reduce space below 90%. If the pool performance recovers, then you know that this particular pool's workload performs best below 90%.

               

              Thanks, Cindy