Re: Very low disk performance Highpoint 1820a

From: Steven Hartland (killing_at_multiplay.co.uk)
Date: 04/28/05

  • Next message: Arne : "Re: Very low disk performance Highpoint 1820a" 
    To: "Eric Anderson" <anderson@centtech.com>
Date: Thu, 28 Apr 2005 17:08:10 +0100

    ----- Original Message -----
    From: "Eric Anderson" <anderson@centtech.com>

    > Correct - I misread the dd line. When you are doing the dd, what is
    > your system busy doing? (top/ps info)

    The machine is idle only me doing the test via an ssh session.

    > What do you suspect?

    I really dont know what it could be driver issue? iirc scott wrote / converted
    this one from source direct form highpoint so maybe he could have some
    useful imput here.

    > Some info from one of my arrays:
    >
    > # dd if=/dev/zero of=./testfile bs=64k count=10000
    > 10000+0 records in
    > 10000+0 records out
    > 655360000 bytes transferred in 3.581413 secs (182989226 bytes/sec)
    >
    > (unmount / mount filesystem)
    > # dd if=./testfile of=/dev/null bs=64k count=10000
    > 10000+0 records in
    > 10000+0 records out
    > 655360000 bytes transferred in 6.747707 secs (97123362 bytes/sec)
    >
    > # dd if=/dev/da0s1d of=/dev/null bs=64k count=10000
    > 10000+0 records in
    > 10000+0 records out
    > 655360000 bytes transferred in 11.252226 secs (58242699 bytes/sec)
    >
    > Seems like the reads should be faster than the writes..

    Hmm just tried the write and I get:
    dd if=/dev/zero of=./testfile bs=64k count=10000
    10000+0 records in
    10000+0 records out
    655360000 bytes transferred in 5.237026 secs (125139727 bytes/sec)

    Which is 2.5 times quicker than read which is really just not
    right.

    Issue with /dev/null?

        Steve / K

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  • Next message: Arne : "Re: Very low disk performance Highpoint 1820a"

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