From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: raid 5 to raid 6 reshape gone bad Date: Sun, 13 Nov 2011 14:55:56 +1100 Message-ID: <20111113145556.45b04397@notabene.brown> References: <4dq3p8xsef.ln2@goaway.wombat.san-francisco.ca.us> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/9iIP1g0SG5OVVJ35PdH1UI3"; protocol="application/pgp-signature" Return-path: In-Reply-To: <4dq3p8xsef.ln2@goaway.wombat.san-francisco.ca.us> Sender: linux-raid-owner@vger.kernel.org To: Keith Keller Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/9iIP1g0SG5OVVJ35PdH1UI3 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Sat, 12 Nov 2011 19:33:24 -0800 Keith Keller wrote: > On 2011-11-13, Travis Brown wrote: > > I was reshaping my 5 drive raid 5 with spare to a raid 6 array when the= drive I was using for my backup went offline. If that's not murphy's law,= I don't know what is. The array is still up and usable, but I'm afraid to= reboot or doing anything to it, really. Suggestions on getting this thing= back to usable are very welcome.=20 >=20 > > Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [r= aid4] [raid10]=20 > > md126 : active raid6 sde3[0] sdf3[3] sdb3[1] sdd3[4] sdc3[2] > > 5856728064 blocks super 0.91 level 6, 512k chunk, algorithm 18 [5= /4] [UUUU_] >=20 > Do you have hot-swap drives? If so, simply mark sdd3 as faulty with > mdadm, remove it from the array, then physically remove and replace it > and use mdadm to add the new drive. The raid6 should start to rebuild > automatically. Not good advice. This is about reshaping, not rebuilding. I'm sorry, but I think you've completely missed the point. NeilBrown >=20 > If you don't have hot-swap drives, you should still be able to use mdadm > to set faulty and remove sdd3, shut down, replace sdd, and reboot. Make > sure your /etc/mdadm.conf file is up to date and accurate before > shutting down. Alternatively, make sure mdadm *won't* probe for raid > arrays, and instead assemble it manually after booting; that might be a > more sure way to do it. Either way, with four working disks your new > raid6 can still suffer one more drive failure and still be usable. >=20 > Of course, insert the standard disclaimer about RAID not being a > replacement for backups. :) If it won't take too long, you might > consider doing and/or refreshing your backups before attempting > anything. (The hot-swap method is reasonably safe as long as you're > *positive* you're removing the correct disk.) >=20 > --keith >=20 >=20 >=20 --Sig_/9iIP1g0SG5OVVJ35PdH1UI3 Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBTr8/zDnsnt1WYoG5AQKSbA/+MzK/C2OOlUvOwMa0od3XdBQ43LwJyZWD lFuwQzOoRbBSJVF4NIX1AzQXmkACAvKfQfRtfWYKtNa0LrBWvt+1NXoejx4RE3CK /EeeMP/e2LBHP+uF5Z5AHNiNS6F+sf3usVZx1BvyjsvFzI1pe4YECcxGLEFWgMAZ atbzUHd0AkzQVB7ndL9l88M5fHXu5zMWQvmAPRdwVHXrRog1zTinxFQq5ODHZfGE hPqzxEqNKQBwh7H1zF8c7xdRwFQzhWYqZ7FlxDv7EqN7wDOyZkt8fxXgPM62r5A5 e3MU4v/bndwSvvicHkcK7zzHTrZmKBltr0caWpVmbjNQpAHMu024th6FLKsdDZFT vi+RKLlPfTa6U6MimBMWmRYC6pvTyK5RLjri5+3QwN0uSzjWwdJ03b+8FoUGAWGG ylaH7HgA9xEyxiJWueO75QYShpzvVYIoOz/DAkC/SIyTKbq6N2bZLUMseDL6sPsY 4MnBaWjfj7eZohzbkIubVkRGJSr0fMRTYLt7eogxqczRpfwoqfQ5doTTaSAMAFWQ C6Pz9FrCQR+QoIMEUcCiFa9/hUv7+rSAxiiGir0QBAEtvlRqtoYYs6N20kU8IZ1P W0R8xOBFoJJYV3MBtNfdf9C6Bmqm+byoZhVhfIrlIIfMyEItQWcT3AJVQR1pBRyM mRxVV1S3EXc= =bIH2 -----END PGP SIGNATURE----- --Sig_/9iIP1g0SG5OVVJ35PdH1UI3--