From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Mailand Subject: Re: ceph and ext4 Date: Mon, 14 Nov 2011 21:08:17 +0100 Message-ID: <4EC17531.3090805@tuxadero.com> References: <4EC10664.1080501@tuxadero.com> <4EC118A1.1030008@tuxadero.com> Reply-To: martin@tuxadero.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from einhorn.in-berlin.de ([192.109.42.8]:50744 "EHLO einhorn.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754370Ab1KNUI0 (ORCPT ); Mon, 14 Nov 2011 15:08:26 -0500 In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Sage Weil Cc: Gregory Farnum , ceph-devel@vger.kernel.org so snapshots of rbd images would be safe? or would they hit the limit? Sage Weil schrieb: > On Mon, 14 Nov 2011, Gregory Farnum wrote: >> On Mon, Nov 14, 2011 at 5:33 AM, Martin Mailand wrote: >>> Hi Tomasz, >>> as far as I know it still has this limit. >>> But it should be relatively safe to use it. >>> >>> http://marc.info/?l=ceph-devel&m=131942130322957&w=2 >>> >>> If we hit the 4KB limit of xattrs in ext4 how does it show up in the rbd >>> layer? >>> >>> How does it show up in the fs layer, would the fs still be clean? >> Right now it would show up very badly, unfortunately. (And yes, the >> limit is still there.) You'd notice, though you might manage to >> corrupt some of your data first. :/ > > Well, the osd's are now more careful about being fail-stop, so if they hit > the xattr limit they crash. So there won't be data corruption per se, > except that you won't be able to start the OSD up again because the > journal replay will keep hitting the limit. > >> However, if you're not taking snapshots and you're not using xattrs >> yourself, you won't hit it with rbd or the Ceph FS. > > Right. Nothing sets large xattrs on objects in rbd. For the file system, > this would only happen on extremely (!) deeply nested directories (ceph > dfs xattrs are managed by the MDS, not as object attrs). > > sage > > >> -Greg >> >>> -martin >>> >>> >>> Am 14.11.2011 14:09, schrieb Tomasz Paszkowski: >>>> what about limit on xattr size ? Is it still limited to 4KB ? >>>> >>>> >>>> >>>> On Mon, Nov 14, 2011 at 1:15 PM, Martin Mailand >>>> wrote: >>>>> Hi Christian, >>>>> I am not sure if you noticed, but your ext4 bug is fixed in mainline. I >>>>> am >>>>> running a ceph cluster with 40+ vms for over a week by now, without any >>>>> problems. An fsck.ext4 shows the ext4 is clean. >>>>> The performance of ext4 is much better than btrfs, no rise in the load of >>>>> the osd's. >>>>> >>>>> -martin >>>>> -- >>>>> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >>>>> the body of a message to majordomo@vger.kernel.org >>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>>> >>>> >>>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >> -- >> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >>