From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from 220-245-31-42.static.tpgi.com.au ([220.245.31.42]:48487 "EHLO smtp.sws.net.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750900AbaEGFga (ORCPT ); Wed, 7 May 2014 01:36:30 -0400 In-Reply-To: References: <1541415.olHfkWYf4R@zafu> <3839313.LSaoXm11Qk@zafu> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Subject: Re: Using noCow with snapshots ? From: Russell Coker Date: Wed, 07 May 2014 15:36:15 +1000 To: Duncan <1i5t5.duncan@cox.net>, linux-btrfs@vger.kernel.org Message-ID: <16fd4391-5c16-42a6-82a2-9bd1cb988906@email.android.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: How could BTRFS and a database "fight" about data recovery? BTRFS offers similar guarantees about data durability etc to other journalled filesystems and only differs by having checksums so that while a snapshot might have half the data that was written by an app you at least know that the half will be consistent. If you had database files on a separate subvol to the database log then you would be at risk of having problems making a any sort of consistent snapshot (the Debian approach of /var/log/mysql and /var/lib/mysql is a bad idea). But there would be no difference with LVM snapshots in that regard. -- Sent from my Samsung Galaxy Note 2 with K-9 Mail.