Date: Fri, 14 May 1999 11:41:42 +0400 (MSD) From: "Sergey Ayukov (mailing lists)" <asv1@crydee.sai.msu.ru> To: Cy Schubert - ITSD Open Systems Group <Cy.Schubert@uumail.gov.bc.ca> Cc: stable@FreeBSD.ORG Subject: Re: NFS question.. Message-ID: <Pine.BSF.4.05.9905132030110.14051-100000@crydee.sai.msu.ru> In-Reply-To: <199905131334.GAA32197@cwsys.cwsent.com>
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On Thu, 13 May 1999, Cy Schubert - ITSD Open Systems Group wrote: > > NFSD Host OS Network Throughput, KB/s Comments > > speed Read Write > > FreeBSD 3.1 100 4500 610 ! vfs.nfs.async=1 > > FreeBSD 3.1 100 550 vfs.nfs.async=0 > > FTP->FreeBSD 100 6000 3000 > > FreeBSD 3.1 10 1040 560 vfs.nfs.async=1 > > FreeBSD 3.1 10 330 vfs.nfs.async=0 > > Linux 10 1020 800 ! > > Solaris 7 (i386) 10 900 480 > > I don't think that this is an NFS issue. You'll generally find that > write local filesystem performance of FreeBSD is slower on FreeBSD than > on Linux. Linux filesystems are written asynchronously while FreeBSD > by default writes metadata synchronously (SMD). SMD (Synchronous > Metadata) writes are not the same as synchronous writes (all writes to > the filesystem being synchronous) -- sync option on the mount command. Actually, the remedy for slow writes has been identified. Thanks to all who replied. After doing /sbin/sysctl -w vfs.nfs.async=1 /sbin/sysctl -w vfs.nfs.gatherdelay=0 I get about 2.9MB/s on write over clean 100MBit/s network (this will violate NFSv2 specs since server will report that operation is completed before actual write). Thank you for explanation about filesystem internals; I think the performance difference due to SMD is much smaller than the 2.1MB/s difference I was getting. > IIRC, Bruce Evans made the comment last year that by mounting a > filesystem async, he had an incredible performance improvement. I'm > sorry I cannot recall the actual percentage of performance improvement. I did try it (added async to options in fstab), but NFS performance seemed to be almost unaffected. --------------------------------------------------------------------------- Dr. Sergey Ayukov Sternberg Astronomical Institute http://www.ayukov.com Moscow, Russia http://crydee.sai.msu.ru/index-asv.html To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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