Date: Mon, 30 Apr 2012 07:58:01 -0400 (EDT) From: Rick Macklem <rmacklem@uoguelph.ca> To: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl> Cc: freebsd-hackers@freebsd.org Subject: Re: NFS - slow Message-ID: <1970100135.114428.1335787081556.JavaMail.root@erie.cs.uoguelph.ca> In-Reply-To: <alpine.BSF.2.00.1204300708060.30254@wojtek.tensor.gdynia.pl>
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Wojciech Puchar wrote: > > the server is required to do that. (ie. Make sure the data is stored > > on > > stable storage, so it can't be lost if the server crashes/reboots.) > > Expensive NFS servers can use non-volatile RAM to speed this up, but > > a generic > > FreeBSD box can't do that. > > > > Some clients (I believe ESXi is one of these) requests FILE_SYNC all > > the > > time, but all clients will do so sooner or later. > > > > If you are exporting ZFS volumes and don't mind violating the NFS > > RFCs > > and risking data loss, there is a ZFS option that helps. I don't use > > ZFS, but I think the option is (sync=disabled) or something like > > that. > > (ZFS folks can help out, if you want that.) Even using > > vfs.nfsrv.async=1 > > breaks the above. > > > thank you for answering. i don't use or plan to use ZFS. and i am > aware of > this NFS "feature" but i don't understand - even with syncs disabled, > why > writes are not clustered. i always see 32kB writes in systat > The old (default on NFSv3) server sets the maximum wsize to 32K. The new (default on 9) sets it to MAXBSIZE, which is currently 64K, but I would like to get that increased. (A quick test suggested that the kernel works when MAXBSIZE is set to 128K, but I haven't done much testing yet.) > > when running unfsd from ports it doesn't have that problem and works > FASTER than kernel nfs. But you had taken out fsync() calls, which breaks the protocol, as above. rick > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to > "freebsd-hackers-unsubscribe@freebsd.org"
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