Date: Sat, 5 May 2001 15:41:07 +1200 From: "Juha Saarinen" <juha@saarinen.org> To: "Mike Smith" <msmith@freebsd.org>, "Tadayuki OKADA" <tadayuki@mediaone.net> Cc: "stable" <stable@freebsd.org> Subject: RE: soft update should be default Message-ID: <KPECIILENDDLPCNIMLOFAEJKCDAA.juha@saarinen.org> In-Reply-To: <200105050142.f451gsl05388@mass.dis.org>
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:: 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 <julian@freebsd.org> To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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