Dell, Compaq Servers and Linux

[pando]

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?

[Shestakov]

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.

[pando]

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

[Shestakov]

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]

[pando]

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

[Shestakov]

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]