Date: Fri, 13 Jan 2006 13:10:48 -0800 (PST) From: Arne Woerner <arne_woerner@yahoo.com> To: Slawek Zak <slawek.zak@gmail.com>, freebsd-database@freebsd.org, freebsd-performance@freebsd.org Subject: Re: Horrible PostgreSQL performance with NFS Message-ID: <20060113211048.31785.qmail@web30313.mail.mud.yahoo.com> In-Reply-To: <787bbe1c0601131220j7b3a052ege5fe4683156312a7@mail.gmail.com>
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Hiho! --- Slawek Zak <slawek.zak@gmail.com> wrote: > A couple of days ago I've moved our > production database from local disks > to NetAPP filer serving NFS. Performance > for this server dropped by factor of 10 > if not more. > I would like to suggest some tests (I do not have a clear idea, why your system becomes slower; a hypothesis will follow below): 1. benchmark the local disc (watch cpu usage via e. g. vmstat 1) % dd if=/dev/zero of=/some/local/filesystem/a bs=1m count=1000 2. benchmark the NFS filesystem (watch cpu usage via e. g. vmstat 1) % dd if=/dev/zero of=/some/NFS/filesystem/a bs=1m count=1000 3. test the NIC performance with (again watching the CPU usage might help) % ping -s 50000 <nfs-server> I get 17Mbit/sec which is the actual rate... neo# ping -s 50000 vaako PING vaako.riddick.homeunix.org (10.1.1.3): 50000 data bytes 50008 bytes from 10.1.1.3: icmp_seq=0 ttl=64 time=46.584 ms My theory would be, that your NICs need a lot of CPU time, while your local discs dont need so much CPU time. :-) Bye Arne __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
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