From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: rebuild raid6 after two failures Date: Wed, 1 Feb 2012 16:31:57 +1100 Message-ID: <20120201163157.1605ec8c@notabene.brown> References: <8eekv8xpcn.ln2@goaway.wombat.san-francisco.ca.us> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/FYwmFqQo1Ppn059U.tb3kXL"; protocol="application/pgp-signature" Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Keith Keller Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/FYwmFqQo1Ppn059U.tb3kXL Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Tue, 31 Jan 2012 20:42:28 -0800 Keith Keller wrote: > On 2012-01-31, Keith Keller wrote: > > > > I recently had a RAID6 lose two drives in quick succession, with one > > spare already in place. The rebuild started fine with the spare, but > > now that I've replaced the failed disks, should I expect the current > > rebuild to finish, then rebuild on another spare? >=20 > [snip] >=20 > Well, for better or worse, this is now a moot question--I had another > drive kicked out of the array, I believe prematurely by the controller. > I was able to --assemble --force the array, and it is now rebuilding > two spares instead of one. AFAIR there was no activity on the > filesystem at the time, so I am optimistic that the filesystem should be > fine after an fsck. Thanks to the advice from last time which suggested > --assemble --force instead of --assume-clean in this situation. >=20 > Could it have been the older version of mdadm that didn't tell the > kernel to start rebuilding the added spare? I have made 3.2.3 my > default mdadm, which I hope alleviates some of the issues I've had with > rebuilds not starting. (As an aside, I've also bitten the bullet and > decided to swap out all the WD-EARS drives for real RAID drives; ideally > I'd replace the controller, but I don't want to invest the time needed > to replace and test all the components properly.) If a spare is being rebuild when another spare is added, it keeps with the first rebuild rather than restarting from the beginning. This means that you get some redundancy sooner, which is probably a good thing. NeilBrown --Sig_/FYwmFqQo1Ppn059U.tb3kXL Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBTyjOTTnsnt1WYoG5AQLTQRAAiXKBexsvoODFo7Hc3Qpp8ghvIADbOWex FZWgk3tDWrJ8b09Bwf1bVnkCa09f5DNnGzgXeaoi12aQmZvujeG1j3+FVGl07w6/ Hpe2z52Qjmvjqo6SpX/s9aO6cgRh5OYSKa8WCZL9PDBNnk2W1OptLPFpcFGkXMTt FmsyZRRqYfFe8TjifYM5ZKMYBT+atw7b8z0ZsXLiEuZDv/F8ctehOF04CoOVfGvL l/9ic3tCv1NYP6dj2CGVwY2x69uHrROUpIXQvW+UFYmuM9ABlXO7v2u7opl0pzEk BotU+ynKpDjBVik6CgYemGGUwigb5fczUyzmvKJb6ev3A+tlk5VH6R6qlQ70SlkW YOI75hrQohGaSM6ZPjSbgfsYdgfpa/aePQ/mQ6UXO3B5qCdqv10U1FXYUP1yghnq WVOX6bW/18C0ngV9h+HMcURVToETVIf/ByjjcX6GebKb3/tNPaBvaAGgR6KxbnfX ZqF3Q+PPPA0mJ468M9dHSuWddR6QTZj+FQo66dDn46iS0hTfNvvjwATJrXl4gmuJ 00waaXZcYsJv/CrZyAhz2MSkg1631JtXWaFvEGUIczqyKyG/JJXTJVF7zCuZTf9J CeYH1Vk6mrCnbg9o6ZqC9TY8+g4eVO7NE84kZ7Fdxgjj895hOhMiGcqdXFt0OU+u O+aKzp1ZqCw= =1iLt -----END PGP SIGNATURE----- --Sig_/FYwmFqQo1Ppn059U.tb3kXL--