From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Fick Subject: Re: RBD/OSD questions Date: Thu, 6 May 2010 15:28:42 -0700 (PDT) Message-ID: <719233.66260.qm@web36101.mail.mud.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from web36101.mail.mud.yahoo.com ([66.163.179.215]:47192 "HELO web36101.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753703Ab0EFW2n convert rfc822-to-8bit (ORCPT ); Thu, 6 May 2010 18:28:43 -0400 Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Sage Weil Cc: =?iso-8859-1?Q?Cl=E1udio_Martins?= , ceph-devel@vger.kernel.org --- On Thu, 5/6/10, Sage Weil wrote: > The image is striped over objects, _then_ the objects are > replicated across OSDs.=A0 Objects themselves aren't striped. >=20 > For example, if an image is striped over objects A B C D E > F, each 4MB, you might end up with >=20 > osd0: A=A0 B' C=A0 D=A0 E' F' > osd1: A' B=A0 C' D' E=A0 F >=20 > where A is the primary copy, A' is the replica, etc. Yes, I see now, much clearer, thanks. So, as long as each object has one copy on each OSD it=20 should be safe. And there might be some hash based=20 extra non-perfect stripping as a benefit. Then, yeah, it does seem like it would be hard to find a very=20 unbalanced workload on a heterogeneous OSD (even with=20 a 2 node cluster). Cool. Thanks, -Martin =20 -- 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