Date: Mon, 28 Nov 2011 15:29:13 +0100 From: Bengt Ahlgren <bengta@sics.se> To: Daryl Sayers <daryl@ci.com.au> Cc: freebsd-stable@freebsd.org Subject: Re: Low nfs write throughput Message-ID: <uh7sjl8l3ra.fsf@P142.sics.se> In-Reply-To: <201111180310.pAI3ARbZ075115@mippet.ci.com.au> (Daryl Sayers's message of "Fri, 18 Nov 2011 14:10:27 %2B1100 (EST)") References: <201111180310.pAI3ARbZ075115@mippet.ci.com.au>
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Daryl Sayers <daryl@ci.com.au> writes: > Can anyone suggest why I am getting poor write performance from my nfs setup. > I have 2 x FreeBSD 8.2-STABLE i386 machines with ASUS P5B-plus mother boards, > 4G mem and Dual core 3g processor using 147G 15k Seagate SAS drives with > onboard Gb network cards connected to an idle network. The results below show > that I get nearly 100Mb/s with a dd over rsh but only 15Mbs using nfs. It > improves if I use async but a smbfs mount still beats it. I am using the same > file, source and destinations for all tests. I have tried alternate Network > cards with no resulting benefit. [...] > Looking at a systat -v on the destination I see that the nfs test does not > exceed 16KB/t with 100% busy where the other tests reach up to 128KB/t. > For the record I get reads of 22Mb/s without and 77Mb/s with async turned on > for the nfs mount. On an UFS filesystem you get NFS writes with the same size as the filesystem blocksize. So an easy way to improve performance is to create a filesystem with larger blocks. I accidentally found this out when I had two NFS exported filesystems from the same box with 16K and 64K blocksizes respectively. (Larger blocksize also tremendously improves the performance of UFS snapshots!) Bengthome | help
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