Date: Mon, 10 Apr 2006 12:38:01 -0500 From: Eric Anderson <anderson@centtech.com> To: Nicolas KOWALSKI <Nicolas.Kowalski@imag.fr> Cc: freebsd-fs@freebsd.org Subject: Re: [patch] giant-less quotas for UFS Message-ID: <443A97F9.8090601@centtech.com> In-Reply-To: <vqolkudv09k.fsf@corbeau.imag.fr> References: <20060329152608.GB1375@deviant.kiev.zoral.com.ua> <vqoy7ydv7lw.fsf@corbeau.imag.fr> <20060410144904.GC1408@deviant.kiev.zoral.com.ua> <vqou091v3vt.fsf@corbeau.imag.fr> <443A7C8E.4020203@centtech.com> <vqopsjpv2ci.fsf@corbeau.imag.fr> <443A8842.6060802@centtech.com> <vqolkudv09k.fsf@corbeau.imag.fr>
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Nicolas KOWALSKI wrote: > Eric Anderson <anderson@centtech.com> writes: > >> Nicolas KOWALSKI wrote: >>> Yes, this is exactly what is happening. To add some precision, some >>> students here use calculation applications >>> that allocate a lot of disk space, ususally more than their allowed >>> home quotas; when by error they launch these apps in their home >>> directories, instead of their workstation dedicated space, it makes >>> the server go to its knees on the NFS client side. >> When you say 'to it's knees' - what do you mean exactly? How many >> clients do you have, how much memory is on the server, and how many >> nfsd threads are you using? What kind of load average do you see >> during this (on the server)? > > Sorry for the imprecision. > > The server is a Dual-Xeon 2.8Ghz, 2GB of RAM, using SCSI3 Ultra320 > 76GB disks and controller. It is accessed by NFS from ~100 Unix > (Linux, Solaris) clients, and by Samba from ~15 Windows XP. The > network connection is GB ethernet. > > During slowdowns, it's only from a NFS client view that the server > does not respond. For example, a simple 'ls' in my home directory is > almost immediate, but when it slows down, it can take up to 2 minutes. > > On the server, the load average goes to 0.5, compared to a default > maximum of 0.15-0.20. The nfsd processus shows them in the state > "biowr" in top, but nothing is really written, because the quotas > system block any further writes to the user exceeding her/his quotas. > In this case (which is what I suspected), try bumping up your nfsd threads to 128. I set mine very high (I have around 1000 clients), and I can say there aren't really ill-effects besides a bit of memory usage (which you have plenty of). I suspect increasing the threads will neutralize this problem for you. Eric -- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology Anything that works is better than anything that doesn't. ------------------------------------------------------------------------
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