From owner-freebsd-hackers@FreeBSD.ORG Tue Oct 7 16:42:35 2008 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9D12B1065788 for ; Tue, 7 Oct 2008 16:42:35 +0000 (UTC) (envelope-from zbeeble@gmail.com) Received: from wx-out-0506.google.com (wx-out-0506.google.com [66.249.82.234]) by mx1.freebsd.org (Postfix) with ESMTP id 547CA8FC0A for ; Tue, 7 Oct 2008 16:42:35 +0000 (UTC) (envelope-from zbeeble@gmail.com) Received: by wx-out-0506.google.com with SMTP id s17so764544wxc.7 for ; Tue, 07 Oct 2008 09:42:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type:references; bh=0T9nz1rflil8vljRYMwgWRHiMQrOn0weOWNk3CkstX0=; b=ACKWxD13yPgFYSDwowpSaWQFwmVNxF46BGUkpZu+t0GUBgsydU0daMymuv/TD6SnL6 Is5RUZRK+UZEKOcz+bpOJjEPxXJ3fny+OCSxbF6a2kaG+itfZmC6BrxvwC4XWa5ZPKkP hdcSmJX/rjOeuMaOY6y+fkLi6gBVjtk5KMkhU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:references; b=AZbV+VwjE5iF/OoPNxOAAdE8zuelY/tk4gJcj14Pufz7uZ71ZKVlSRvF45VoZ4bQY6 RPONTM3eyggT+AvClLqJZQNuojpC+BtFuNrNM/Ym6WgBOz2nrK3UjrKDPb+XiIevmN7G EjLJRON+HNTp0ksjlirwpDphqelc0cTut7Cvk= Received: by 10.151.156.15 with SMTP id i15mr10042365ybo.184.1223397753979; Tue, 07 Oct 2008 09:42:33 -0700 (PDT) Received: by 10.150.137.11 with HTTP; Tue, 7 Oct 2008 09:42:33 -0700 (PDT) Message-ID: <5f67a8c40810070942k317d55f4i5d46b1409ef34034@mail.gmail.com> Date: Tue, 7 Oct 2008 12:42:33 -0400 From: "Zaphod Beeblebrox" To: "Shaun Amott" In-Reply-To: <20081007155059.GA20615@charon.picobyte.net> MIME-Version: 1.0 References: <48E9E1BB.6020908@ispro.net> <48EA3451.7040801@miralink.com> <48EA83CE.4060702@ispro.net> <20081007155059.GA20615@charon.picobyte.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: Sean Bruno , Evren Yurtesen , freebsd-hackers@freebsd.org Subject: Re: continuous backup solution for FreeBSD X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 07 Oct 2008 16:42:35 -0000 On Tue, Oct 7, 2008 at 11:50 AM, Shaun Amott wrote: > On Tue, Oct 07, 2008 at 12:31:58AM +0300, Evren Yurtesen wrote: > > > > so FreeBSD could be supported also. As you can imagine, it is not only > > important that data can be restored when a box hardware failure etc. it > is > > also important that data can be restored if deleted by accidents etc. > While > > traditional backup programs provide this functionality, you cant really > go > > back to 10 min or 1h ago, often they take daily backups and have to scan > > whole filesystem for changed files every time the backup is taken which > > stresses out the systems. > > > > This can (more or less) be achieved with snapshots: you can cheaply > maintain old versions of the file system, and mount an old snapshot at > any time. Hourly is about as fine-grained as you can expect though. > Unfortunately, as mentioned on another recent thread, FreeBSD UFS snapshots are quite fragile. The last time I tried this type-of-thing, it rather quickly resulted in filesystem corruption on moderately busy filesystems. Also, the cost of UFS snapshots (in time, while locking the filesystem) are unacceptable in practice. Now... ZFS seems to do this well enough. I use snapshots and send snapshots to my backup server --- it all seems to work OK. The idea that snapshots have infinite granularity and are automatic (introduced to me by the Hammer filesystem document) has merit, though --- and this is certainly core to the featurelist of the company that started this thread .