From owner-freebsd-stable@FreeBSD.ORG Sat Mar 2 00:48:40 2013 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 0BBC6E13; Sat, 2 Mar 2013 00:48:40 +0000 (UTC) (envelope-from dmagda@ee.ryerson.ca) Received: from eccles.ee.ryerson.ca (eccles.ee.ryerson.ca [141.117.1.2]) by mx1.freebsd.org (Postfix) with ESMTP id AA9A91F09; Sat, 2 Mar 2013 00:48:39 +0000 (UTC) Received: from [10.0.1.2] (bas2-toronto09-1176131079.dsl.bell.ca [70.26.86.7]) (authenticated bits=0) by eccles.ee.ryerson.ca (8.14.4/8.14.4) with ESMTP id r220iMNx034719 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Fri, 1 Mar 2013 19:44:23 -0500 (EST) (envelope-from dmagda@ee.ryerson.ca) Subject: Re: Musings on ZFS Backup strategies Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: text/plain; charset=us-ascii From: David Magda In-Reply-To: Date: Fri, 1 Mar 2013 19:45:17 -0500 Content-Transfer-Encoding: quoted-printable Message-Id: <4642A367-1404-4AD9-9EEF-7496006400CF@ee.ryerson.ca> References: <20130301165040.GA26251@anubis.morrow.me.uk> To: Daniel Eischen X-Mailer: Apple Mail (2.1283) Cc: freebsd-stable@freebsd.org X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 02 Mar 2013 00:48:40 -0000 On Mar 1, 2013, at 12:23, Daniel Eischen wrote: > dump (and ufsdump for our Solaris boxes) _just work_, and we > can go back many many years and they will still work. If we > convert to ZFS, I'm guessing we'll have to do nightly > incrementals with 'tar' instead of 'dump' as well as doing > ZFS snapshots for fulls. Keep some snapshots, and send stuff to tape after a certain amount of = time. Most (though not all) restores are usually within "x" weeks, where = "x" is a different value for each organization. (Things will be = generally asymptotic though.) So if you keep 1 week worth of snapshots, you'll probably end being able = to service (say) 25% of restore requests: the file can be grabbed = usually from yesterday's snapshot. If you keep 2 weeks' worth of = snapshots, probably catch 50% of requests. 4 weeks will give you 80%; 6 = weeks, 90%; 8 weeks, 95%.=20 Of course the more snapshots, the more spinning disk you need (using = power and generating heat). Most articles describing backup/restore best practices I've read in the = last few years have stated you want to use disk first (snapshots, VTLs, = etc.), and then clone to tape after a certain amount of time ("x" = weeks). Or rather: disk AND tape, then clone to another tape (so you = have two) and purge the disk copy after "x". So in this instance, keep snapshots around for a little while, and keep = doing your tape backups for long-term storage. Also inform people about = the .snapshot/ directory so they can possibly do some "self service" in = case they fat finger something (quicker for them, and less hassle for = help desk/IT).