From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from magic.merlins.org ([209.81.13.136]:41568 "EHLO mail1.merlins.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753843AbaEEBps (ORCPT ); Sun, 4 May 2014 21:45:48 -0400 Date: Sun, 4 May 2014 18:04:29 -0700 From: Marc MERLIN To: Brendan Hide Cc: linux-btrfs@vger.kernel.org Subject: Re: Copying related snapshots to another server with btrfs send/receive? Message-ID: <20140505010429.GC10159@merlins.org> References: <20140504031231.GG9061@merlins.org> <5365E932.20602@swiftspirit.co.za> <20140504072829.GK9061@merlins.org> <5365F23E.8070009@swiftspirit.co.za> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <5365F23E.8070009@swiftspirit.co.za> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Sun, May 04, 2014 at 09:54:38AM +0200, Brendan Hide wrote: > Yes, -p (parent) and -c (clone source) are the only ways I'm aware > of to push subvolumes across while ensuring data-sharing > relationship remains intact. This will end up being much the same as > doing incremental backups: > From the man page section on -c: > "You must not specify clone sources unless you guarantee that > these snapshots are exactly in the same state on both sides, the > sender and the receiver. It is allowed to omit the '-p ' > option when '-c ' options are given, in which case 'btrfs > send' will determine a suitable parent among the clone sources > itself." Right. I had read that, but it was not super clear to me how it can be useful, especially if it's supposed to find the source clone by itself. >>From what you said and what I read, I think the source might be allowed to be read write, otherwise it would be simpler for btrfs send to know that the source has not changed. I think I'll have to do more testing with this when I get some time. Thanks, Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/ | PGP 1024R/763BE901