Date: Fri, 18 Nov 2011 08:14:42 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-stable@freebsd.org Cc: Daryl Sayers <daryl@ci.com.au> Subject: Re: Low nfs write throughput Message-ID: <201111180814.42656.jhb@freebsd.org> In-Reply-To: <201111180310.pAI3ARbZ075115@mippet.ci.com.au> References: <201111180310.pAI3ARbZ075115@mippet.ci.com.au>
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On Thursday, November 17, 2011 10:10:27 pm Daryl Sayers wrote: > > 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. > > oguido# dd if=/u0/tmp/D2 | rsh castor dd of=/dsk/ufs/D2 > 1950511+1 records in > 1950511+1 records out > 998661755 bytes transferred in 10.402483 secs (96002246 bytes/sec) > 1950477+74 records in > 1950511+1 records out > 998661755 bytes transferred in 10.115458 secs (98726301 bytes/sec) (98Mb/s) > > > oguido# mount -t nfs -o wsize=65536,rsize=65536,tcp gemini:/dsk/ufs /mnt > oguido# dd if=/u0/tmp/D2 of=/mnt/tmp/D2 bs=128k > 7619+1 records in > 7619+1 records out > 998661755 bytes transferred in 62.570260 secs (15960646 bytes/sec) (15Mb/s) > > > oguido# mount -t nfs -o wsize=65536,rsize=65536,tcp,async gemini:/dsk/ufs /mnt > oguido# dd if=/u0/tmp/D2 of=/mnt/tmp/D2 bs=128k > 7619+1 records in > 7619+1 records out > 998661755 bytes transferred in 50.697024 secs (19698627 bytes/sec) (19Mb/s) > > > oguido# mount -t smbfs //gemini/ufs /mnt > oguido# dd if=/u0/tmp/D2 of=/mnt/tmp/D2 bs=128k > 7619+1 records in > 7619+1 records out > 998661755 bytes transferred in 29.787616 secs (33526072 bytes/sec) (33Mb/s) > > 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. I don't know if it will help with your performance, but I have some patches to allow the NFS server to cluster writes. You can try www.freebsd.org/~jhb/patches/nfs_server_cluster.patch. I've tested it on 8, but it should probably apply fine to 9. -- John Baldwin
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