From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Chandler Subject: Re: Synching a Backup Server Date: Sun, 09 Jan 2011 11:46:59 +0000 Message-ID: <4D29A033.7000803@chandlerfamily.org.uk> References: <201101060935.14059.CACook@quantum-sci.com> <201101061342.23991.CACook@quantum-sci.com> <201101071720.08298.hka@qbs.com.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed To: linux-btrfs@vger.kernel.org Return-path: In-Reply-To: <201101071720.08298.hka@qbs.com.pl> List-ID: On 07/01/11 16:20, Hubert Kario wrote: > > I usually create subvolumes in btrfs root volume: > > /mnt/btrfs/ > |- server-a > |- server-b > \- server-c > > then create snapshots of these directories: > > /mnt/btrfs/ > |- server-a > |- server-b > |- server-c > |- snapshots-server-a > |- @GMT-2010.12.21-16.48.09 > \- @GMT-2010.12.22-16.45.14 > |- snapshots-server-b > \- snapshots-server-c > > This way I can use the shadow_copy module for samba to publish the snapshots > to windows clients. > Can you post some actual commands to do this part I am extremely confused about btrfs subvolumes v the root filesystem and mounting, particularly in relation to the default subvolume. For instance, if I create the initial file system using mkfs.btrfs and then mount it on /mnt/btrfs is there already a default subvolume? or do I have to make one? What happens when you unmount the whole filesystem and then come back The wiki also makes the following statement *"Note:* to be mounted the subvolume or snapshot have to be in the root of the btrfs filesystem." but you seems to have snapshots at one layer down from the root. I am trying to use this method for my offsite backups - to a large spare sata disk loaded via a usb port. I want to create the main filesystem (and possibly a subvolume - this is where I start to get confused) and rsync my current daily backup files to it. I would then also (just so I get the correct time - rather than do it at the next cycle, as explained below) take a snapshot with a time label. I would transport this disk offsite. I would repeat this in a months time with a totally different disk In a couple of months time - when I come to recycle the first disk for my offsite backup, I would mount the retrieved disk (and again I am confused - mount the complete filesystem or the subvolume?) rsync (--inplace ? - is this necessary) again the various backup files from my server and take another snapshot. I am hoping that this would effectively allow me to leave the snapshot I took last time in place, as because not everything will have changed it won't have used much space - so effectively I can keep quite a long stream of backup snapshots in place offsite. Eventually of course the disk will start to become full, but I assume I can reclaim the space by deleting some of the old snapshots. -- Alan Chandler http://www.chandlerfamily.org.uk