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3 Replies Latest reply: Jun 14, 2013 9:06 AM by cindys RSS

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

984266 Newbie
Currently Being Moderated

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 Pro
    Currently Being Moderated

    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 Newbie
    Currently Being Moderated

    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 Pro
    Currently Being Moderated

    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