From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Mitchell Subject: Re: test osd on zfs Date: Fri, 19 Apr 2013 06:47:24 -0400 Message-ID: <517120BC.8060205@gmail.com> References: <516E7D5C.7080309@nazarianin.com> <516ECFB6.8090107@gmail.com> <516EF07E.4000909@llnl.gov> <516EF34E.5000000@profihost.ag> <516F0321.2@inktank.com> <516F10BE.6020103@llnl.gov> <38892EC8-F082-4AC4-8B6D-F8A541DBC7B7@profihost.ag> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-vb0-f45.google.com ([209.85.212.45]:65188 "EHLO mail-vb0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757487Ab3DSKr2 (ORCPT ); Fri, 19 Apr 2013 06:47:28 -0400 Received: by mail-vb0-f45.google.com with SMTP id w15so3448997vbf.4 for ; Fri, 19 Apr 2013 03:47:27 -0700 (PDT) In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Alex Elsayed Cc: ceph-devel@vger.kernel.org Alex Elsayed wrote: > Since Btrfs has implemented raid5/6 support (meaning raidz is only a feature > gain if you want 3x parity, which is unlikely to be useful for an OSD[1]), > the checksumming may be the only real benefit since it supports sha256 (in > addition to the non-cryptographic fletcher2/fletcher4), whereas btrfs only > has crc32c at this time. Plus (in my real-world experience) *far* better robustness. If Ceph could use either and both had feature parity, I'd choose ZFS in a heartbeat. I've had too many simple Btrfs filesystems go corrupt, not even using any fancy RAID features. I wasn't aware that Ceph was using btrfs' file-scope clone command. ZFS doesn't have that, although in theory with the new capabilities system it could be supported in one implementation without requiring an on-disk format change. --Jeff