From owner-freebsd-fs@FreeBSD.ORG Tue Jan 11 02:01:37 2005 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8998216A4D0 for ; Tue, 11 Jan 2005 02:01:37 +0000 (GMT) Received: from web30305.mail.mud.yahoo.com (web30305.mail.mud.yahoo.com [68.142.200.98]) by mx1.FreeBSD.org (Postfix) with SMTP id 2FD5943D39 for ; Tue, 11 Jan 2005 02:01:37 +0000 (GMT) (envelope-from barath_yes@yahoo.com.sg) Received: (qmail 57584 invoked by uid 60001); 11 Jan 2005 02:01:36 -0000 Message-ID: <20050111020136.57582.qmail@web30305.mail.mud.yahoo.com> Received: from [203.118.46.137] by web30305.mail.mud.yahoo.com via HTTP; Tue, 11 Jan 2005 10:01:36 CST Date: Tue, 11 Jan 2005 10:01:36 +0800 (CST) From: Barath S To: Poul-Henning Kamp , Kris Kennaway In-Reply-To: <45044.1105365790@critter.freebsd.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit cc: FreeBsd-MailGrp cc: Scott Long Subject: Re: using mfs of size > 64Mb and system stability X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 Jan 2005 02:01:37 -0000 Where can I get details regarding the 'preload' backed ram disks ?. How is it different from "malloc" based ram disks? As per 'man mdconfig', there is no such option available. Could you kindly provide me more hints on this? Thanks --- Poul-Henning Kamp wrote: > In message > <20050110135747.GA44905@xor.obsecurity.org>, Kris > Kennaway writes: > > > >--HlL+5n6rz5pIUxbD > >Content-Type: text/plain; charset=us-ascii > >Content-Disposition: inline > >Content-Transfer-Encoding: quoted-printable > > > >On Mon, Jan 10, 2005 at 11:11:44AM +0100, > Poul-Henning Kamp wrote: > >> In message > <20050110100840.29845.qmail@web30301.mail.mud.yahoo.com>, > Bara= > >th S w > >> rites: > >> >Initially, I didn't go for swap based fs as I > felt > >> >that the memory occupied will be from the swap > area. > >> >As you are saying that the allocation will be > from > >> >buffer/cache, I will test swap-mfs. > >>=20 > >> malloc backing should not be used for large > disks. > >>=20 > >> If you _truly_ want to have a large disk which is > memory backed, > >> you should consider using the "preload" backing > as this will withdraw > >> the memory entirely from the kernels use. > >>=20 > >> In general, the benefit from using RAM disks is > much smaller than > >> most people realize. > > > >I've found that using a swap-backed disk > substantially cuts back on > >disk accesses for my purposes [...] > > Swap-backing is very different from RAM disks in > that things get > pushed out of RAM if better use can be made of the > pages. > > With RAM disks (preload or malloc backing) you > occupy valuable > RAM pages with free diskblocks. > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > phk@FreeBSD.ORG | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be > explained by incompetence. > __________________________________________________ Do You Yahoo!? Download the latest ringtones, games, and more! http://sg.mobile.yahoo.com