Date: Mon, 30 Apr 2012 07:09:43 +0200 (CEST) From: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl> To: Rick Macklem <rmacklem@uoguelph.ca> Cc: freebsd-hackers@freebsd.org Subject: Re: NFS - slow Message-ID: <alpine.BSF.2.00.1204300708060.30254@wojtek.tensor.gdynia.pl> In-Reply-To: <1715805628.104139.1335733226336.JavaMail.root@erie.cs.uoguelph.ca> References: <1715805628.104139.1335733226336.JavaMail.root@erie.cs.uoguelph.ca>
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> 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 when running unfsd from ports it doesn't have that problem and works FASTER than kernel nfs.
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