From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Mamedov Subject: Re: Upgrading from RAID 5 to 6 or build native level 6? Date: Sat, 19 Feb 2011 17:28:42 +0500 Message-ID: <20110219172842.5bc79f44@natsu> References: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/R+28nxhfxQ2XQ0H2HE+mDPF"; protocol="application/pgp-signature" Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Beolach Cc: Lasse Jensen , linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/R+28nxhfxQ2XQ0H2HE+mDPF Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Fri, 18 Feb 2011 19:02:07 -0700 Beolach wrote: > That information is incomplete or out-of-date. During a RAID 5 to > RAID 6 reshape, there may be an intermediate step where all of the Q > parity blocks are stored on one disk, but as the reshape continues, it > will move all the Q parity blocks to a normal RAID 6 layout. IIRC, in > the very early stages of RAID 5 to RAID 6 reshape development, it > would leave it in the abnormal layout, but that has not been the case > for quite some time. And I believe in some cases a RAID 5 to RAID 6 > reshape will not even use the intermediate step w/ the abnormal > layout. After the reshape fully completes, it is exactly the same as > a RAID 6 array built from scratch. See man mdadm --layout=3Dpreserve vs --layout=3Dnormalise. I am not sure which one of these is the default, but it is definitely still possible to convert RAID5 to RAID6 (while adding one disk) without restripi= ng, and to me this looks like a very useful feature, not something outdated. --=20 With respect, Roman --Sig_/R+28nxhfxQ2XQ0H2HE+mDPF Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iEYEARECAAYFAk1ft3sACgkQTLKSvz+PZwgyTACfYuPZMGraOimTSoUvw3ZIAKVk wN4Anj9+l7SbOzyqQs6Ji7KpYoha7G34 =WYlt -----END PGP SIGNATURE----- --Sig_/R+28nxhfxQ2XQ0H2HE+mDPF--