Date: Mon, 10 Jan 2005 05:57:47 -0800 From: Kris Kennaway <kris@obsecurity.org> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: Scott Long <scottl@freebsd.org> Subject: Re: using mfs of size > 64Mb and system stability Message-ID: <20050110135747.GA44905@xor.obsecurity.org> In-Reply-To: <41247.1105351904@critter.freebsd.dk> References: <20050110100840.29845.qmail@web30301.mail.mud.yahoo.com> <41247.1105351904@critter.freebsd.dk>
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[-- Attachment #1 --] On Mon, Jan 10, 2005 at 11:11:44AM +0100, Poul-Henning Kamp wrote: > In message <20050110100840.29845.qmail@web30301.mail.mud.yahoo.com>, Barath 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. > > malloc backing should not be used for large disks. > > 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. > > 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 (package building, where everything that hits disk will be deleted again in a few minutes). It appears to give a reasonable performance boost, which I'm still trying to measure. Unfortunately, swap-backed md under 6.x deadlocks under some conditions which are being investigated. Kris [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (FreeBSD) iD8DBQFB4onbWry0BWjoQKURAoRMAKDe4IyajL2SoKlKR+PvJBMS3gaeWwCg8vm8 Gq8hke7Io29IXodGpr1RQn4= =FgCB -----END PGP SIGNATURE-----home | help
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