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  1. #1
    Join Date
    Aug 2004
    Posts
    346

    Sata Hard Drive Optimization, How...?

    On my server P IV 3GHz (HT enabled) I have 2x200GB sata HD and I have very very high load and 85% IOWAIT, IDLE 0%!

    Also I have 2GB RAM, swap 0K used!

    Centos 3.5, cPanel...

    I don`t know why but "hdparm -i /dev/sda" don`t work:
    /dev/sdb:
    operation not supported on SCSI disks

    (but I don`t have SCSI disks)

    Can I on some other way check my hard drives informations?

    Here is speed test:

    hdparm -Tt /dev/sda

    /dev/sda:
    Timing buffer-cache reads: 2924 MB in 2.00 seconds = 1462.00 MB/sec
    Timing buffered disk reads: 82 MB in 3.05 seconds = 26.89 MB/sec

    hdparm -Tt /dev/sdb

    /dev/sdb:
    Timing buffer-cache reads: 2996 MB in 2.00 seconds = 1498.00 MB/sec
    Timing buffered disk reads: 2 MB in 31.41 seconds = 65.20 kB/sec


    From this you can see that my Hard Drive 2 work very slow and I think this HD generate this IO problem (this is on working server)...

    hdparm /dev/sda

    /dev/sda:
    readonly = 0 (off)
    geometry = 24321/255/63, sectors = 390719855, start = 0

    hdparm /dev/sdb

    /dev/sdb:
    readonly = 0 (off)
    geometry = 24321/255/63, sectors = 390721968, start = 0


    Can I on some way optimize this HDs for better speed?

    Thanks.

  2. #2
    1) backup the data first of all from that slow hdd

    2) find an admin

  3. #3
    Join Date
    Oct 2004
    Location
    Southwest UK
    Posts
    1,175
    I'd be looking more for a replacement HDD. I don't think that level of poor performance can be optimised away, especially as its come from a benchmark test program (ie and not real-world reading of a file).

    The only thing I can think of, besides it being knackered, is heavy fragmentation. Is the 2nd HDD more full than the first?

  4. #4
    Join Date
    Aug 2004
    Posts
    346
    Yes, 78% full...
    1st 61% full...

    Now I stop apache and here is new benchmark:
    hdparm -Tt /dev/sda

    /dev/sda:
    Timing buffer-cache reads: 3660 MB in 2.00 seconds = 1830.00 MB/sec
    Timing buffered disk reads: 180 MB in 3.02 seconds = 59.60 MB/sec

    hdparm -Tt /dev/sdb

    /dev/sdb:
    Timing buffer-cache reads: 3768 MB in 2.00 seconds = 1884.00 MB/sec
    Timing buffered disk reads: 174 MB in 3.02 seconds = 57.62 MB/sec


    Now both work much better! Can this be better?

  5. #5
    Join Date
    Apr 2004
    Location
    Australia
    Posts
    419
    I suggest you have a chat to thelinuxguy, its his lane down the iowait way

  6. #6
    Join Date
    Aug 2004
    Posts
    346
    Somebody know can this tutorial help to me:
    http://www.phpportals.com/modules.ph...warticle&id=19

    ??

    This is very old tutorial and if I good see this is not for SATA HDs!??

    When I use command:

    hdparm /dev/sda

    this is result:
    /dev/sda:
    readonly = 0 (off)
    geometry = 24321/255/63, sectors = 390719855, start = 0

    not like in this tutorial:
    /dev/hda:

    multcount = 0 (off)

    I/O support = 0 (default 16-bit)

    unmaskirq = 0 (off)

    using_dma = 0 (off)

    keepsettings = 0 (off)

    nowerr = 0 (off)

    readonly = 0 (off)

    readahead = 8 (on)

    geometry = 1870/255/63, sectors = 30043440, start = 0


    Thanks.

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