From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Helmut Hullen" Subject: Re: How Snapshots Inter-relate? Date: 22 Apr 2011 17:39:00 +0200 Message-ID: References: <1303411647.25281.2.camel@ayu> Reply-To: helmut@hullen.de Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII To: linux-btrfs@vger.kernel.org Return-path: In-Reply-To: <1303411647.25281.2.camel@ayu> List-ID: Hallo, Calvin, Du meintest am 21.04.11: >> I have set up a backup server in the garage which does rsync backups >> of all my servers weekly, and snapshots those backups. [...] > You have nothing to worry about. You can delete any snapshot on btrfs > without losing data from any other snapshot. Each snapshot is > completely independent. > This works because data which is shared between multiple snapshots is > reference counted, and won't be deleted until you remove the last > snapshot that references that data. That sounds like "hard links"; I use that with my favourite backup program "rsnapshot". I like it. But: if the (only) target of the (many) hard links fails, then it fails in all backups. It's a very good idea to make monthly or yearly backups of one such hard linked backup to another disk. Viele Gruesse! Helmut