From owner-freebsd-scsi Fri Oct 18 17:23:45 2002 Delivered-To: freebsd-scsi@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 76DCB37B404 for ; Fri, 18 Oct 2002 17:23:44 -0700 (PDT) Received: from rootlabs.com (root.org [67.118.192.226]) by mx1.FreeBSD.org (Postfix) with SMTP id ED0D643E6E for ; Fri, 18 Oct 2002 17:23:38 -0700 (PDT) (envelope-from nate@rootlabs.com) Received: (qmail 47811 invoked by uid 1000); 19 Oct 2002 00:23:40 -0000 Date: Fri, 18 Oct 2002 17:23:40 -0700 (PDT) From: Nate Lawson To: Mike Thompson Cc: freebsd-scsi@freebsd.org Subject: Re: Multiple FreeBSD SCSI Hosts In-Reply-To: <4.3.2.7.2.20021018162828.00b0b4d0@pop.atomz.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Fri, 18 Oct 2002, Mike Thompson wrote: > At 03:41 PM 10/18/02 -0700, Nate Lawson wrote: > >What are you trying to achieve? If you are trying to have apps on two > >boxes sharing data via this method (say a webserver cluster), you're going > >to end up with consistency problems from the FILE SYSTEM. SCSI is not the > >problem -- multiple initiators have been around forever. > > I'm trying to essentially keep a live hot spare that can be manually > configured to take over for the primary server should it fail for some > reason. The secondary really doesn't need access to the shared SCSI volume > until such time. Considering the problems mentioned regarding the file > system it would probably be best for the secondary to not mount the shared > SCSI volume until the primary has unmounted it (or been turned off). > > Mike Excellent choice and that should work fine. You could even not have the drive detected until the main box crashes: if (heartbeat_dead) { camcontrol rescan 0 fsck /dev/daX mount /dev/daX /recovery/mnt notify_admin() } -Nate To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message