From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from atl4mhob13.myregisteredsite.com ([209.17.115.51]:49722 "EHLO atl4mhob13.myregisteredsite.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754459AbaCOQAe (ORCPT ); Sat, 15 Mar 2014 12:00:34 -0400 Received: from mailpod1.hostingplatform.com ([10.30.71.115]) by atl4mhob13.myregisteredsite.com (8.14.4/8.14.4) with ESMTP id s2FG0Wl6031998 for ; Sat, 15 Mar 2014 12:00:32 -0400 Message-ID: <5324794D.80802@chinilu.com> Date: Sat, 15 Mar 2014 09:01:17 -0700 From: George Mitchell Reply-To: george@chinilu.com MIME-Version: 1.0 To: linux-btrfs@vger.kernel.org Subject: Re: Incremental backup for a raid1 References: <1564384.fRV1HUkfCq@fuchsia> <2106363.nA97oxn4hn@fuchsia> <53224D57.8020308@chinilu.com> <1789445.UA8sCrE2Cn@fuchsia> In-Reply-To: <1789445.UA8sCrE2Cn@fuchsia> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Michael, I am currently using rsync INSTEAD of btrfs backup tools. I really don't see anyway that it could be compatible with the backup features of btrfs. As I noted in my post, it is definitely not a perfect solution, but it is doing the job for me. What I REALLY want in this regard is n-way mirroring to get me out of the simplex trap completely. At that point, I can have more confidence in btrfs snapshop capability. On 03/15/2014 04:35 AM, Michael Schuerig wrote: > On Thursday 13 March 2014 17:29:11 George Mitchell wrote: >> I currently use rsync to a separate drive to maintain a >> backup copy, but it is not integrated into the array like n-way would >> be, and is definitely not a perfect solution. > Could you explain how you're using rsync? I was just about to copy a > btrfs filesystem to another disk. That filesystem has several subvolumes > and about 100 snapshots overall. Owing to COW, this amounts to about > 1.2TB. However, I reckon that rsync doesn't know anything about COW and > accordingly would blow up my data immensely on the destination disk. > > How do I copy a btrfs filesystem preserving its complete contents? How > do I update such a copy? > > Yes, I want to keep the subvolume layout of the original and I want to > copy all snapshots. I don't think send/receive is the answer, but it's > likey I don't understand it well enough. I'm concerned, that a > send/receive-based approach is not robust against mishaps. > > Consider: I want to incrementally back-up a filesystem to two external > disks. For this I'd have to for each subvolume keep a snapshot > corresponding to its state on the backup disk. If I make any mistake in > managing these snapshots, I can't update the external backup anymore. > > Also, I don't understand whether send/receive would allow me to > copy/update a subvolume *including* its snapshots. > > Things have become a little more complicated than I had hoped for, but > I've only been using btrfs for a couple of weeks. > > Michael >