From owner-freebsd-stable Fri May 4 20:41:42 2001 Delivered-To: freebsd-stable@freebsd.org Received: from vimfuego.saarinen.org (saarinen.org [203.79.82.14]) by hub.freebsd.org (Postfix) with ESMTP id 2661637B423; Fri, 4 May 2001 20:41:39 -0700 (PDT) (envelope-from juha@saarinen.org) Received: from dendennis.saarinen.org ([192.168.1.2] helo=dendennis) by vimfuego.saarinen.org with smtp (Exim 3.22 #1 (Red Hack)) id 14vswr-00075u-01; Sat, 05 May 2001 15:41:37 +1200 From: "Juha Saarinen" To: "Mike Smith" , "Tadayuki OKADA" Cc: "stable" Subject: RE: soft update should be default Date: Sat, 5 May 2001 15:41:07 +1200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2911.0) In-Reply-To: <200105050142.f451gsl05388@mass.dis.org> Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG :: It requires disabling of write caching, which typically reduces :: performance (significantly). What? That doesn't seem to be mentioned anywhere. In fact, http://www.freebsd.org/doc/en_US.ISO_8859-1/books/handbook/internals-vm.html says: "Run time VM and system tuning is relatively straightforward. First, use softupdates on your UFS/FFS filesystems whenever possible. /usr/src/contrib/sys/softupdates/README contains instructions (and restrictions) on how to configure it up." su-2.05# less /usr/src/sys/ufs/ffs/README.softupdates $FreeBSD: src/sys/ufs/ffs/README.softupdates,v 1.7.2.1 2000/06/26 14:09:01 sheldonh Exp $ Add option SOFTUPDATES to your kernel configuration. You should also read the copyrights in the sources and the README file. Once you're running a kernel with soft update support, you need to enable it for whichever filesystems you wish to run with the soft update policy. This is done with the -n option to tunefs(8) on the UNMOUNTED filesystems, e.g. from single-user mode you'd do something like: tunefs -n enable /usr To permanently enable soft updates on the /usr filesystem (or at least until a corresponding ``tunefs -n disable'' is done). For more general information on soft updates, please see: http://www.ece.cmu.edu/~ganger/papers/CSE-TR-254-95/ Why do you have to disable write caching? -- Julian Elischer To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message