From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amon Ott Subject: Re: ceph stability Date: Fri, 21 Dec 2012 11:07:55 +0100 Message-ID: <50D434FB.4020909@m-privacy.de> References: <50D1C09E.9000504@inktank.com> <50D3213A.2080401@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from www.m-privacy.de ([85.214.237.71]:47389 "EHLO www.m-privacy.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751429Ab2LUKIF (ORCPT ); Fri, 21 Dec 2012 05:08:05 -0500 In-Reply-To: <50D3213A.2080401@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Mark Nelson Cc: Roman Hlynovskiy , ceph-devel@vger.kernel.org Am 20.12.2012 15:31, schrieb Mark Nelson: > On 12/20/2012 01:08 AM, Roman Hlynovskiy wrote: >> Hello Mark, >> >> for multi-mds solutions do you refer to multi-active arch or 1 activ= e >> and many standby arch? >=20 > That's a good question! I know we don't really recommend multi-activ= e > right now for production use. Not sure what our current recommendati= ons > are for multi-standby. As far as I know it's considered to be more > stable. I'm sure Greg or Sage can chime in with a more accurate > assessment. We have been testing a lot with multi-standby, because a single MDS doe= s not make a lot of sense in a cluster. Maybe the clue is to have only on= e standby, making SPOF a DPOF? Up to 0.55 with some of Yan's fixes, Ceph has been too instable wheneve= r it came to MDS failover. As long as the same MDS has been kept active, it was quite stable. We are really hoping for 0.56 with the additional MDS fixes and also fixed kernel 3.8 code. We have been waiting to replace our existing cluster fs with CephFS for at least one and a half years, but it has never been stable enough in our setup with standby MDS and takeover, le= t alone multi-active. We do not want to risk a complete cluster failure. Amon Ott --=20 Dr. Amon Ott m-privacy GmbH Tel: +49 30 24342334 Am K=F6llnischen Park 1 Fax: +49 30 99296856 10179 Berlin http://www.m-privacy.de Amtsgericht Charlottenburg, HRB 84946 Gesch=E4ftsf=FChrer: Dipl.-Kfm. Holger Maczkowsky, Roman Maczkowsky GnuPG-Key-ID: 0x2DD3A649 -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html