It is the CPU load on the client. The dd/IOR process is using one core completely. The clients and the servers are connected via DDR IB. LNET bandwidth is at 1.8 GB/s. Servers have 1.8.3, the client has 1.8.3 patchless.
Micha Am 20.10.2010 18:15, schrieb Andreas Dilger: > 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.kl...@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.kl...@tu-dresden.de >> WWW: http://www.tu-dresden.de/zih >> _______________________________________________ >> Lustre-discuss mailing list >> Lustre-discuss@lists.lustre.org >> http://lists.lustre.org/mailman/listinfo/lustre-discuss > -- Michael Kluge, M.Sc. Technische Universität Dresden Center for Information Services and High Performance Computing (ZIH) D-01062 Dresden Germany Contact: Willersbau, Room WIL A 208 Phone: (+49) 351 463-34217 Fax: (+49) 351 463-37773 e-mail: michael.kl...@tu-dresden.de WWW: http://www.tu-dresden.de/zih _______________________________________________ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss
