From owner-freebsd-hackers Fri May 7 9:46:59 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [209.157.86.2]) by hub.freebsd.org (Postfix) with ESMTP id 48C7815327 for ; Fri, 7 May 1999 09:46:56 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.9.3/8.9.1) id JAA45627; Fri, 7 May 1999 09:46:10 -0700 (PDT) (envelope-from dillon) Date: Fri, 7 May 1999 09:46:10 -0700 (PDT) From: Matthew Dillon Message-Id: <199905071646.JAA45627@apollo.backplane.com> To: Chris Costello Cc: "Ronald G. Minnich" , hackers@FreeBSD.ORG Subject: Re: memory-based VFS References: <19990507092008.A580@holly.dyndns.org> Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG :On Fri, May 7, 1999, Ronald G. Minnich wrote: :> The v9fs memory-based VFS, written by Aaron Marks, is available at :> http://www.acl.lanl.gov/~rminnich/ : : Doesn't this do the same thing as MFS? Not to detract from the cool things people have been writing, but in FreeBSD-current, it is possible to directly swap-back the VN device and mount a softupdates-enabled filesystem over it. You effectively get a memory filesystem due to the way the standard VM cache works. MFS is also a memory filesystem, but MFS wastes memory because the data representing a block exists in two places ( non-shared ) - the MFS process's VM space, and in the system VM cache. With the VN device, you wind up with more swap activity but ( probably ) better VM management - it doesn't starve memory and force defensive paging like MFS does. There are some very cool things coming down the pipe in the next 6 months. Poul has some excellent ideas on how to fix the VFS/BIO I/O subsystem. -Matt Matthew Dillon :> This is intended to serve as the basis of private name spaces for FreeBSD. :> I have a VFS and full implementation for Linux kernel 2.0.x, soon to go on :> the web page too. :> :> Anyone who'd like to talk to me about private name spaces for freebsd, :> give me a ring. :> :> ron :-- :Chris Costello :Me and my two friends... GIF and Wesson. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message