Dell, Compaq Servers and Linux
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Thread: Dell, Compaq Servers and Linux

  1. #1
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    I have some problems with Dell Servers, somehow in Compaq Servers when I install Suse Linux I can see the SCSI controller prettyy good, for example if I do

    df -h

    it shows somthing like

    /dev/dsk/c0t0d0s0

    in Dell Servers (happens in two alread) I see something like

    /dev/sda1

    I suspect it is not recognising the SCSI controller in Dell but since I have seen in two already is this normal?

  2. #2
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    try to check is /dev/sda* are links to /dev/s0... devices or not
    ls -la /dev/sda*
    if u will see something like :
    brw-rw---- 1 root root 9 Jun 7 14:41 /dev/scd1 -> /dev/c0t0d1s0
    or
    lrwxrwxrwx 1 root root 9 Jun 7 14:43 /dev/cdrom -> /dev/scd0

    then dell variant of suse linux just reflect "phisical name" of disk devises to "logical"
    may be i'm wrong.

  3. #3
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    the suse linux I used for both servers are the same CDs

    the funny thing is iostat in DELL shows something like

    dev-xxx
    dev-yyy and shows the stats

    in Compaq shows the stats without device names
    I will check the symbolic links

  4. #4
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    This isn't just links, this is difference of device specification between unix(sysV) and linux.
    in unix (by history) using channel/controller, disk, partition specification.
    in linux inteface/type of unit/partition.

    /dev/dsk/c0t0d0s0 --> unix sysV standart notation
    /dev/scd1 --> linux standart notation


    [Edited by Shestakov on 07-15-2002 at 08:17 PM]

  5. #5
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    hm then how come in Compaq servers I do see /dev/dsk/c0t0d0s0 but not in Dell servers

    I am having a problem is in a Compaq Server everything is fast and smooth but in a Dell server database is extremely slow, whenever there is some batch job or a big update going I start to see free buffer waits in v$session_wait and noone can get in. I have patched to 8.1.7.4 since there was a bug which cause buffer waits in 8.1.7.0.1 but after patching I still have the same problem so I suspect it's a OS configuration problem. I am trying to find out how to determine if async i/o is used in Linux. The other difference I noticed is that Compaq sees the SCSI Adapter perfectly but not in Dell althoguh I am not 100% sure if this is the problem.
    Basically I am trying to determine what is the difference between the Compaq Server and Dell server at OS level (not the hardware since the SGA settings are similar). I am ignoring RAID now even Dell is running on RAID 5 and Compaq on RAID 0+1 because although RAID 5 is slow I dont believe a simple update of 500000 rows would lock the whole database with free buffer waits

    I have increased db writer with no luck

  6. #6
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    As i can remember Compaq proliant has 3 separate buses (data/command/addresses or some thing like this)
    Dell has only 1 standart bus.
    May be this is problem with perfomace of scsii controllers on dell boxes.

    [Edited by Shestakov on 07-15-2002 at 08:15 PM]

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