Date: Tue, 4 Jun 2002 10:54:26 -0500 From: Dan Nelson <dnelson@allantgroup.com> To: Terry Todd <tlt@badger.tltodd.com> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: FreeBSD 5.0dp1 nfs server to Red Hat nfs client extremely slow Message-ID: <20020604155426.GB46396@dan.emsphone.com> In-Reply-To: <20020604103039.A11587@badger.tltodd.com> References: <20020603102416.A98405@badger.tltodd.com> <20020603152547.A32050@xor.obsecurity.org> <20020604103039.A11587@badger.tltodd.com>
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In the last episode (Jun 04), Terry Todd said: > Here's more data: > All comparisons were done by running: > time dd if=/dev/zero of=somefile bs=1024k count=256 > > NFS server NFS client transfer time > Red Hat 2.2.16-22 Slackware 2.2.20 0m25.48s > Red Hat 2.2.16-22 FreeBSD 4.4-RELEASE 46.902824 secs > Slackware 2.2.20 FreeBSD 4.4-RELEASE 49.100937 secs > Slackware 2.2.20 Red Hat 2.2.16-22 0m40.375s > FreeBSD 5.0-DP1 FreeBSD 4.4-RELEASE 52.279700 secs > FreeBSD 5.0-DP1 Slackware 2.2.20 0m55.270s > FreeBSD 5.0-DP1 Red Hat 2.2.16-22 18m12.448s <- 18 Minutes > > I can ftp 268435456 bytes from the FreeBSD 5.0-DP1 to > the Red Hat 2.2.16-22 in 28 seconds. I assume the RedHat 2.2.16 kernel is using NFSv2? NFSv2 requires that all writes be immediately commited to stable storage (i.e. either disk or battery-backed RAM). Chances are the Linux NFS servers are caching writes against spec, which is why they are so fast. A way to check this is to just listen to the disks when you do the copy. An NFSv2 server with no battery-backed RAM should be hammering its disks syncing data (usually a seek per sync). If you want fast NFSv2 mounts, sysctl vfs.nfs.async=1 on the server, but be aware that if the server crashes it could corrupt files in use by the client. If you want fast reliable mounts, upgrade that Redhat box to something that can do NFSv3. -- Dan Nelson dnelson@allantgroup.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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