Re: [Xen-users] 100% iowait in domU with no IO tasks.

[Maarten Vanraes <maarten@xxxxx>]

Hi,

This is also a problem we are having on our xen servers, but the iowait is 
considerably higher.

i would like to reduce iowait as much as possible, i see iowait above 70% 
sometimes...

Sincerely,

Maarten

Op donderdag 8 mei 2008 11:02, schreef Bogdan B. Rudas:
> Hi.
>
> I entered one of our domU tonight and see following problem:
>
> # iowait -k 5
>
> avg-cpu:  %user   %nice %system %iowait  %steal   %idle
>
>            0.00    0.00    0.00  100.00    0.00    0.00
>
> Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
> sda1              0.00         0.00         0.00          0          0
> sda2              0.00         0.00         0.00          0          0
>
> I check other domU and dom0 on same server - there were high iowait: from
> 20% to 50% with few transactions per second and about 0.1-1.5 Mb/sec
> storage bandwith usage per domU. This domU have no disk IO at all but show
> LA 15 and possible higher.
>
> We have 6 domU on 8-core server with 7 FUJITSU  MBB2147RC SAS HDD on DELL
> PERC 5/i RAID controller.
>
> CentOS 5
> Xen 3.1.0
> Kernel 2.6.21
>
> We suffer from this problem for a while on many our xen hosts, it is not a
> single-time issue.
>
> _______________________________________________
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> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users

-- 
Maarten Vanraes
BA NV: IT & Security

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