We did some system profiling and measured the influence of the lkbtbl_size and rsbtbl_size values (dlm config parameters) to the cpu usage. We noticed, that with large number of dlm locks, these values have a measurable impact to the system performance. You might want to have a look at http://www.open-sharedroot.org/Members/marc/blog/blog-on-dlm/red-hat-dlm-__find_lock_by_id/profile-data-with-diffrent-table-sizes Mark On Saturday 27 October 2007 14:57:26 Jos Vos wrote: > On Fri, Oct 26, 2007 at 07:57:18PM -0400, Wendy Cheng wrote: > > 1. 3TB is not "average size". Smaller RG can help with "df" command - > > but if your system is congested, it won't help much. > > The df also takes ages on an almost idle system. Also, the system often > needs to do rsyncs on large trees and this takes a very long time too. > > In <http://sourceware.org/cluster/faq.html#gfs_tuning> it is suggested > that you should then make the RG larger (i.e. less RGs). As this requires > shuffling aroung with TB's of data before recreating a GFS fs, I want to > have some idea of what my chances are that this is usefull. > > > 2. The gfs_scand issue is more to do with the number of glock count. One > > way to tune this is via purge_glock tunable. There is an old write-up in: > > http://people.redhat.com/wcheng/Patches/GFS/readme.gfs_glock_trimming.R4 > > . It is for RHEL4 but should work the same way for RHEL5. > > I'll try. I assume I can do this per system (so that I don't have to > bring the whole cluster down, only stop the cluster services and unmount > the GFS volumes per node)? > > Any chance this patch will make it into the standard RHEL-package? > I want to avoid to maintain my own patched packages, although as long > as gfs.ko is in the separate kmod-gfs package that's doable. > > -- > -- Jos Vos <jos@xxxxxx> > -- X/OS Experts in Open Systems BV | Phone: +31 20 6938364 > -- Amsterdam, The Netherlands | Fax: +31 20 6948204 > > -- > Linux-cluster mailing list > Linux-cluster@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/linux-cluster -- Gruss / Regards, Dipl.-Ing. Mark Hlawatschek http://www.atix.de/ http://www.open-sharedroot.org/ ** ATIX Informationstechnologie und Consulting AG Einsteinstr. 10 85716 Unterschleissheim Deutschland/Germany -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
