Date: Mon, 18 Apr 2005 23:05:57 +0200 From: Willem Jan Withagen <wjw@withagen.nl> To: Claus Guttesen <kometen@gmail.com> Cc: Kris Kennaway <kris@obsecurity.org> Subject: Re: NFS defaults for read/write blocksize....(Was: Re: 5.4/amd64 console hang) Message-ID: <42642135.3040004@withagen.nl> In-Reply-To: <b41c75520504181353ca86951@mail.gmail.com> References: <6eb82e05041500274172afd3@mail.gmail.com> <20050416122222.GA12385@totem.fix.no> <6eb82e0504160536572e068c@mail.gmail.com> <20050416183755.GB61170@xor.obsecurity.org> <4262CFBF.4090709@withagen.nl> <b41c755205041801433fad9c65@mail.gmail.com> <4264104B.2030600@withagen.nl> <b41c75520504181353ca86951@mail.gmail.com>
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Claus Guttesen wrote: >> >>How did you come to this conclusion? What kind of workload? > > > To make a short story long ;-) > > Last year just after christmas I got a new storage system and had an > opportunity to replace our Linux-nfs-server with FreeBSD. I searched > the archives for nfs-related tuning-information, and found some links > suggesting the usage of tcp rather than udp and adjusting the > r/w-size. So I nfs-mounted some clients and started to copy back and > forth. The december release of the (back then) current had some > "server not responding" messages, but they appeared less with > r/w-sizes of 32768. The copying itself was faster as well. > > So I upgraded (two or three times) until I had the Feb. 18'th 2004 > current and the "server not responding" almost vanished. Some weeks > after that the server went into production and have been rock-stable! > It went down once but that was only due to a poweroutage that lasted a > few hours, longest uptime was 117 days before I took it down for > servermaintenance. > > The files are at most some MB in size (images) and some KB (thumbnails). > > >>This is in line with what the graphs suggest: >> Use Laaarrrrrggggeee sizes. > > > And use tcp as well. I would conclude use UDP if they are on the same net/switch. Block reading is more or less equal for both. Block writing is slightly better for UDP, both there is a strange dip for 4Mb filesize. Which was very repeatable, but I can not explain. If you'd have a lot of rewriting, I'd say UDP as well, but 8K szie would be better. --WjW
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