From owner-freebsd-hackers Sun Oct 5 21:01:17 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id VAA29984 for hackers-outgoing; Sun, 5 Oct 1997 21:01:17 -0700 (PDT) (envelope-from owner-freebsd-hackers) Received: from misery.sdf.com (misery.sdf.com [204.244.210.193]) by hub.freebsd.org (8.8.7/8.8.7) with SMTP id VAA29965; Sun, 5 Oct 1997 21:00:32 -0700 (PDT) (envelope-from tom@sdf.com) Received: from tom by misery.sdf.com with smtp (Exim 1.71 #1) id 0xI4Ki-0005Ge-00; Sun, 5 Oct 1997 20:59:48 -0700 Date: Sun, 5 Oct 1997 20:59:43 -0700 (PDT) From: Tom To: Drew Derbyshire cc: hackers@hub.freebsd.org Subject: Re: mount async and possible loss of F/S In-Reply-To: <199710060106.SAA21602@hub.freebsd.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk On Sun, 5 Oct 1997, Drew Derbyshire wrote: > The mount command cheerfully states that the async option is not to be used > unless you are prepared to recreate the file system. Ummm, exactly > what is left so hanging in the wind that you lose the file system rather > than just the recent updates? It really depends on how much disk activity is going on. When async is on, metainfo (directory structures, etc) are not immediately updated. Power failures during during heavy writing will leave a lot of things unwritten, and fsck may not be able to repair things sufficiently without reasonably accurate metainfo. Try it out. Mount /usr/src and /usr/obj async, start a make world, and hit the power switch. Compare the damage to a non-async set. > Thanks > -ahd- > > Tom