From owner-freebsd-fs Thu Dec 14 15: 4: 1 2000 From owner-freebsd-fs@FreeBSD.ORG Thu Dec 14 15:03:59 2000 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from fw.wintelcom.net (ns1.wintelcom.net [209.1.153.20]) by hub.freebsd.org (Postfix) with ESMTP id D678737B402 for ; Thu, 14 Dec 2000 15:03:58 -0800 (PST) Received: (from bright@localhost) by fw.wintelcom.net (8.10.0/8.10.0) id eBEN3sV17950; Thu, 14 Dec 2000 15:03:54 -0800 (PST) Date: Thu, 14 Dec 2000 15:03:54 -0800 From: Alfred Perlstein To: Terry Lambert Cc: Charles Henrich , freebsd-fs@FreeBSD.ORG Subject: Re: Filesystem tuning (minimize seeks) Message-ID: <20001214150353.J4589@fw.wintelcom.net> References: <20001213130138.A25214@sigbus.com> <200012142257.PAA15102@usr08.primenet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <200012142257.PAA15102@usr08.primenet.com>; from tlambert@primenet.com on Thu, Dec 14, 2000 at 10:57:26PM +0000 Sender: bright@fw.wintelcom.net Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org * Terry Lambert [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