From owner-freebsd-stable Mon Feb 21 7:25:54 2000 Delivered-To: freebsd-stable@freebsd.org Received: from point.osg.gov.bc.ca (point.osg.gov.bc.ca [142.32.102.44]) by hub.freebsd.org (Postfix) with ESMTP id 0539237BE2C for ; Mon, 21 Feb 2000 07:25:49 -0800 (PST) (envelope-from Cy.Schubert@uumail.gov.bc.ca) Received: (from daemon@localhost) by point.osg.gov.bc.ca (8.8.7/8.8.8) id HAA00701; Mon, 21 Feb 2000 07:25:46 -0800 Received: from passer.osg.gov.bc.ca(142.32.110.29) via SMTP by point.osg.gov.bc.ca, id smtpda00699; Mon Feb 21 07:25:43 2000 Received: (from uucp@localhost) by passer.osg.gov.bc.ca (8.9.3/8.9.1) id HAA58258; Mon, 21 Feb 2000 07:25:42 -0800 (PST) Received: from cwsys9.cwsent.com(10.2.2.1), claiming to be "cwsys.cwsent.com" via SMTP by passer9.cwsent.com, id smtpdS58251; Mon Feb 21 07:24:47 2000 Received: (from uucp@localhost) by cwsys.cwsent.com (8.9.3/8.9.1) id HAA53892; Mon, 21 Feb 2000 07:24:46 -0800 (PST) Message-Id: <200002211524.HAA53892@cwsys.cwsent.com> Received: from localhost.cwsent.com(127.0.0.1), claiming to be "cwsys" via SMTP by localhost.cwsent.com, id smtpdE53888; Mon Feb 21 07:24:12 2000 X-Mailer: exmh version 2.1.1 10/15/1999 Reply-To: Cy Schubert - ITSD Open Systems Group From: Cy Schubert - ITSD Open Systems Group X-OS: FreeBSD 3.4-RELEASE X-Sender: cy To: "Jeffrey J. Mountin" Cc: Tom , stable@FreeBSD.ORG Subject: Re: Initial performance testing w/ postmark & softupdates... In-reply-to: Your message of "Sat, 19 Feb 2000 03:53:42 CST." <3.0.3.32.20000219035342.009ce460@207.227.119.2> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Mon, 21 Feb 2000 07:24:12 -0800 Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message <3.0.3.32.20000219035342.009ce460@207.227.119.2>, "Jeffrey J. Mounti n" writes: > At 03:08 PM 2/18/00 -0800, Tom wrote: > >On Fri, 18 Feb 2000, Daniel C. Sobral wrote: > > > >> Tom wrote: > >> > > >> > Not really. You could just use async updates instead of softupdates. > >> > Or an OS that uses async updates. Write caching metadata is always > faster > >> > than re-ordering it intelligently. > >> > >> Softupdates reduces the number of writes needed. It can coalesce writes > >> to the same block. > > > > Async updates are always as fast as softupdates, if not faster. You > >should read the softupdates docs. > > As fast, but not safer. > > Can't recall the entire analogy, but Terry mentioned on -hacker a long time > back something to the effect that softupdates is like having a seatbelt and > an airbag rather than just a seatbelt, as well as a faster car too. A paper by Gregory R. Granger and Yale N. Patt of the Departement of EECS, University of Michigan entitled Soft Update: A Solution to the Metadata Update Problem in File Systems discusses softupdate performance v.s. asynchronous write performance. The difference wasn't much, somewhere around 2-3%. Regards, Phone: (250)387-8437 Cy Schubert Fax: (250)387-5766 Team Leader, Sun/DEC Team Internet: Cy.Schubert@uumail.gov.bc.ca UNIX Group, ITSD, ISTA Province of BC "COBOL IS A WASTE OF CARDS." To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message