 | | | FYI: Taroon U3 sluggish issues | FYI: Taroon U3 sluggish issues 2004-11-24 - By Marc Wiatrowski
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If anyone is interested, the beta kernel 2.4.21-23 cleaned up
our problems. Not sure which fix it was, but the difference is
night and day from 2.4.21-20 (I 'd even say its behaving better
than 2.4.21-15 and 2.4.21-9, which seemed about the same)
With just the kernel change network traffic dropped from 16M/sec
to 6M/sec thus dropping the load significantly.
marc
> -- --Original Message-- --
> From: taroon-list-bounces@(protected)
> [mailto:taroon-list-bounces@(protected)] On Behalf Of Marc Wiatrowski
> Sent: Friday, November 05, 2004 12:07 PM
> To: taroon-list@(protected)
> Subject: Taroon U3 sluggish issues
>
> Originally we had a Dell PE650 running RH 7.3 (kernel
> 2.4.18-10) with a
> 2.4 GHz P4 and 512M memory. The application running on this
> server has many
>
> processes, not much local disk io, lots of NFS disk activity
> to a couple
> NetApps,
> and lots of DB interaction with multiple different machine
> running Postgres.
>
> The load on this box was averaging about 6.
>
> Recently we upgraded the machine to another Dell PE750 RHEL
> 3.0 update 3
> (kernel vmlinuz-2.4.21-20.Elsmp) 2.8 GHz P4, 2G memory, and with hyper
> threading
> turned on. So this machine was running the same server jobs
> as before but
> now
> the load jumped up more than double to about 15. I realize
> load is pretty
> general
> especially between two different machines, but the machine
> was noticeably
> much
> slower and applications where taking much longer to run now.
>
> We have tried turning off hyper threading in the bios and went to the
> non-smp kernel
> and that had no effect. Tried playing with
> inactive_clean_percent and this
> had
> no noticeable effect either.
>
> One kicker was we then tried the U2 kernel 2.4.21-15 leaving
> everything else
>
> at U3 and the machine got noticeably better The load dropped
> down to about
> 10.
> The iowait still stayed close to 100%. So it was running
> better, but still
> not as
> good as the "slower " machine running RH 7.3
>
> Then we found NFS defaults had changed from async to sync.
> Forcing async
> appears
> to have dropped the load down to a livable average of about 6.
>
> Network traffic appears to have stayed the same through all
> of this and
> swapping
> has never been an issue. Memory usage is less than 500M. Iowait had
> generally
> been about 100% up to the async change. After that its
> dropped down quite a
> bit.
> In all cases Postgres is the same version and as far as NFS
> its always been
> udp,
> version 3.
>
> Was wondering if anyone is noticing similar issues or know of
> anything else
> that
> has changed between the 2.4.21-15.0.3 and 2.4.21-20 kernels?
> Anything else I
> could
> look at?
>
> thanks for any help,
> marc
>
> ----
> iGLASS NETWORKS
>
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