Date: Thu, 14 Dec 2000 15:03:54 -0800 From: Alfred Perlstein <bright@wintelcom.net> To: Terry Lambert <tlambert@primenet.com> Cc: Charles Henrich <henrich@sigbus.com>, freebsd-fs@FreeBSD.ORG Subject: Re: Filesystem tuning (minimize seeks) Message-ID: <20001214150353.J4589@fw.wintelcom.net> In-Reply-To: <200012142257.PAA15102@usr08.primenet.com>; from tlambert@primenet.com on Thu, Dec 14, 2000 at 10:57:26PM %2B0000 References: <20001213130138.A25214@sigbus.com> <200012142257.PAA15102@usr08.primenet.com>
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* Terry Lambert <tlambert@primenet.com> [001214 14:57] wrote: > > > > Yes, my test is running about 25-50 machines writing a 20mb file to the > > > > FreeBSD box. (The clients are FreeBSD as well). The write is nothing > > > > more than a dd. > > > > I think maybe you've misunderstood my initial question. What Filesystem > > tuning options are there, or any suggestions, to reduce the amount of seeking > > going on when N files are being created and written to at once. I have N > > machines, each one opens a file, writes out a chunk of data, then closes the > > file. Unfortunatly, because all 50 are doing this simultaneously, the data is > > getting written to disk very non-sequentially (From a per file perspective). > > Is there any options to UFS (or via NFSd?) to delay writes, or anything of > > that nature to allow the data to be serialized more often than not? > > The NFS protocol is defined as not returning success unless the > write has been committed to stable storage. In FreeBSD, this > tends to serialize NFS I/O from a single client, and between > multiple clients in excess of the number of nfsiod's you are > running. This is untrue for NFSv3, that's why there are write and commit RPCs. By using write ahead then delaying the commit you can increase performance by only stalling out a single nfsiod to sync out a large section of a file. -- -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org] "I have the heart of a child; I keep it in a jar on my desk." To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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