[Lustre-discuss] high CPU load limits bandwidth?
Andreas Dilger
andreas.dilger at oracle.com
Wed Oct 20 09:15:06 PDT 2010
Is this client CPU or server CPU? If you are using Ethernet it will definitely be CPU hungry and can easily saturate a single core.
Cheers, Andreas
On 2010-10-20, at 8:41, Michael Kluge <Michael.Kluge at tu-dresden.de> wrote:
> Hi list,
>
> is it normal, that a 'dd' or an 'IOR' pushing 10MB blocks to a lustre
> file system shows up with a 100% CPU load within 'top'? The reason why I
> am asking this is that I can write from one client to one OST with 500
> MB/s. The CPU load will be at 100% in this case. If I stripe over two
> OSTs (which use different OSS servers and different RAID controllers) I
> will get 500 as well (seeing 2x250 MB/s on the OSTs). The CPU load will
> be at 100% again.
>
> A 'dd' on my desktop pushing 10M blocks to the local disk shows 7-10%
> CPU load.
>
> Are there ways to tune this behavior? Changing max_rpcs_in_flight and
> max_dirty_mb did not help.
>
>
> Regards, Michael
>
> --
>
> Michael Kluge, M.Sc.
>
> Technische Universität Dresden
> Center for Information Services and
> High Performance Computing (ZIH)
> D-01062 Dresden
> Germany
>
> Contact:
> Willersbau, Room A 208
> Phone: (+49) 351 463-34217
> Fax: (+49) 351 463-37773
> e-mail: michael.kluge at tu-dresden.de
> WWW: http://www.tu-dresden.de/zih
> _______________________________________________
> Lustre-discuss mailing list
> Lustre-discuss at lists.lustre.org
> http://lists.lustre.org/mailman/listinfo/lustre-discuss
More information about the lustre-discuss
mailing list