Hi,

I have 2 server setups, which slightly differ in specs.

Both servers are IBM x336 with RAID 1 on 2 internal disks with RHEL4
installed(2.6.9-42.0.3.ELsmp).
Both with IBM Informix Dynamic Server Version 10.00.UC5

1. One server is without hyperthreading and with a raw disk in LVM.

2. The second server is with hyperthreading and with a raw disk outside
LVM. Just plain raw.

But on the latter server(and only that one) we get this error when
running a large job in informix:
---
requested number of KAIO events (16384) exceeds limit (32) Please
increase the value in /proc/sys/fs/aio-max-nr
---

my sysctl -a | grep aio-max-nr, says (on both machines):

fs.aio-max-nr = 65536

Is my selection of using LVM for raw disks, or the lack of KAIOOFF, etc.
doing stuff differently? does using LVM provide these limitations?

Or what should I boost the number up to?

Sincerely
Max Andersen

Can't answer the original question, but try to switch off hyperthreading on
that second machine and see if it helps.
Intel Hyperthreading on Linux can cause some mysterious Informix
(mal)behaviour, I've seen few unexplainable crashes solved just by removing
Hyperthreading.

"Max Andersen" <max@militant.dk> wrote in message
news:453f79c3$0$20228$edfadb0f@dread16.news.tele.d k...
> Hi,
>
> I have 2 server setups, which slightly differ in specs.
>
> Both servers are IBM x336 with RAID 1 on 2 internal disks with RHEL4
> installed(2.6.9-42.0.3.ELsmp).
> Both with IBM Informix Dynamic Server Version 10.00.UC5
>
> 1. One server is without hyperthreading and with a raw disk in LVM.
>
> 2. The second server is with hyperthreading and with a raw disk outside
> LVM. Just plain raw.
>
> But on the latter server(and only that one) we get this error when running
> a large job in informix:
> ---
> requested number of KAIO events (16384) exceeds limit (32) Please
> increase the value in /proc/sys/fs/aio-max-nr
> ---
>
> my sysctl -a | grep aio-max-nr, says (on both machines):
>
> fs.aio-max-nr = 65536
>
> Is my selection of using LVM for raw disks, or the lack of KAIOOFF, etc.
> doing stuff differently? does using LVM provide these limitations?
>
> Or what should I boost the number up to?
>
> Sincerely
> Max Andersen