From mboxrd@z Thu Jan 1 00:00:00 1970 From: Loic Dachary Subject: Re: Implied parity and erasure code Date: Mon, 12 May 2014 07:39:55 -0400 Message-ID: <5370B30B.4000609@dachary.org> References: <536CF5BA.8040300@dachary.org> <3472A07E6605974CBC9BC573F1BC02E4AE704806@CERNXCHG42.cern.ch> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="H0veHWpJ848uoxJ7J34mCKGq10P72csHl" Return-path: Received: from smtp.dmail.dachary.org ([91.121.254.229]:34061 "EHLO smtp.dmail.dachary.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752579AbaELLkA (ORCPT ); Mon, 12 May 2014 07:40:00 -0400 In-Reply-To: <3472A07E6605974CBC9BC573F1BC02E4AE704806@CERNXCHG42.cern.ch> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Andreas Joachim Peters Cc: Ceph Development This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --H0veHWpJ848uoxJ7J34mCKGq10P72csHl Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 10/05/2014 14:40, Andreas Joachim Peters wrote: > Hi Loic,=20 > I think it is good to have the flexibility to include the global parity= stripes in local subgroups or as in the picture to make a subgroup out o= f the global parities and compute a local paritiy for them. Although with= the chosen parameters these local subgroups are not symmetric (5,5 and 4= chunks per group) but e.g. for 8+4 one would have 3 symmetric local gro= ups as drawn and if you project is on a three data center setup you would= like to have for each center a local parity.=20 >=20 > But wasn't this already possible with your prototype implementation? It was possible to distribute in this way, indeed. But there is no suppor= t for the implied parity idea. I wonder how that would fit. Cheers >=20 > Cheers Andreas. >=20 >=20 >=20 > ________________________________________ > From: Loic Dachary [loic@dachary.org] > Sent: 09 May 2014 17:35 > To: Andreas Joachim Peters > Cc: Ceph Development > Subject: Implied parity and erasure code >=20 > Hi Andreas, >=20 > The "implied parity bloc" mentionned page 4 of http://anrg.usc.edu/~mah= eswaran/Xorbas.pdf is something we've not discussed in the context of the= implementation of the pyramid erasure code plugin. I'm not sure if it wo= uld be useful to have. Do you have an opinion ? >=20 > Cheers >=20 > -- > Lo=EFc Dachary, Artisan Logiciel Libre >=20 --=20 Lo=EFc Dachary, Artisan Logiciel Libre --H0veHWpJ848uoxJ7J34mCKGq10P72csHl Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlNwswsACgkQ8dLMyEl6F20ouACfZS5YjxQAg/RRtFHPcZHrguLj ZTIAn3ynpq1KFC2ROjX80hvhIg/Pq++x =DHBU -----END PGP SIGNATURE----- --H0veHWpJ848uoxJ7J34mCKGq10P72csHl--