SAN performance - Unix

This is a discussion on SAN performance - Unix ; Hi all, System: XioTech Magnitude SAN IBM p5 550 with AIX 5.2 and a Cambex PC2000 FC card. hdisk0 is local hdisk1 is local hdisk2 is on the SAN hdisk3 is on the SAN My issue is when I copy ...

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Thread: SAN performance

  1. SAN performance

    Hi all,

    System:
    XioTech Magnitude SAN
    IBM p5 550 with AIX 5.2 and a Cambex PC2000 FC card.
    hdisk0 is local
    hdisk1 is local
    hdisk2 is on the SAN
    hdisk3 is on the SAN

    My issue is when I copy files either from SAN hdisk to local hdisk, or
    one SAN hdisk to the other SAN hdisk I get about 8 MB/s transfer rate
    (using iostat and the monitoring of the SAN). A 1.5 MB file takes a
    little over 3 minutes. If I transfer that same 1.5 GB file from either
    local hdisk to local hdisk OR local hdisk to SAN hdisk, I get 40 - 60
    MB/s. The file copies in 30 to 40 seconds.
    So basically:
    SAN --> SAN slow
    SAN --> local slow
    local --> SAN fast
    local --> local fast

    XioTech's docs say to change the queue_depth of the SAN hdisks to 8,
    their tech support says to change it to 40, I tried those and kept
    trying all the way up to 256 and saw no difference in performance.

    So I guess my question is, is this normal performance, or is there an
    issue?

    Thanks.


  2. Re: SAN performance

    In article <1116261706.677478.175400@f14g2000cwb.googlegroups. com>,
    "TB" wrote:

    > Hi all,
    >
    > System:
    > XioTech Magnitude SAN
    > IBM p5 550 with AIX 5.2 and a Cambex PC2000 FC card.
    > hdisk0 is local
    > hdisk1 is local
    > hdisk2 is on the SAN
    > hdisk3 is on the SAN
    >
    > My issue is when I copy files either from SAN hdisk to local hdisk, or
    > one SAN hdisk to the other SAN hdisk I get about 8 MB/s transfer rate
    > (using iostat and the monitoring of the SAN). A 1.5 MB file takes a
    > little over 3 minutes. If I transfer that same 1.5 GB file from either
    > local hdisk to local hdisk OR local hdisk to SAN hdisk, I get 40 - 60
    > MB/s. The file copies in 30 to 40 seconds.
    > So basically:
    > SAN --> SAN slow
    > SAN --> local slow
    > local --> SAN fast
    > local --> local fast
    >
    > XioTech's docs say to change the queue_depth of the SAN hdisks to 8,
    > their tech support says to change it to 40, I tried those and kept
    > trying all the way up to 256 and saw no difference in performance.
    >
    > So I guess my question is, is this normal performance, or is there an
    > issue?
    >
    > Thanks.


    Do the Fibre connections go straight from the SAN controller to the AIX
    box or is there a Fibre router in between? If so, perhaps it's causing
    the problem. Can you remove it to see if there's still a transfer
    bottleneck?

    --
    DeeDee, don't press that button! DeeDee! NO! Dee...




  3. Re: SAN performance

    Sorry, Should have mentioned that. No, there is no switch. P2P.


  4. Re: SAN performance

    Sorry, Should have mentioned that. No, there is no switch. P2P.


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