From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: Failed Array Rebuild advice Please Date: Thu, 12 Apr 2012 12:25:55 +1000 Message-ID: <20120412122555.598c0e12@notabene.brown> References: <1334097164.41181.YahooMailNeo@web125506.mail.ne1.yahoo.com> <20120411090219.78392784@notabene.brown> <1334117647.68845.YahooMailNeo@web125505.mail.ne1.yahoo.com> <20120411144302.35f13f3d@notabene.brown> <1334196647.20850.YahooMailNeo@web125501.mail.ne1.yahoo.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/kdAosdFUTjZrL=rpq1fQQe6"; protocol="application/pgp-signature" Return-path: In-Reply-To: <1334196647.20850.YahooMailNeo@web125501.mail.ne1.yahoo.com> Sender: linux-raid-owner@vger.kernel.org To: jahammonds prost Cc: Linux RAID List-Id: linux-raid.ids --Sig_/kdAosdFUTjZrL=rpq1fQQe6 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable On Wed, 11 Apr 2012 19:10:47 -0700 (PDT) jahammonds prost wrote: > > I think it is best to recover, and then reshape later. > =A0 > Which is what I did. The destructive badblocks ran fine overnight, with n= o errors on the drives that were failed out of the array. Interestingly one= of the additional drives that I want to add took an additional 6 hours to = run badblocks, so I need to look into that a bit. > =A0 > I am having a bit of an issue with the reshape tho... When I try and add = one of the 2 additional devices I want to add (I'm going to add them one at= a time), I get an error about the bitmap needing to be removed. > =A0 > =A0=A0=A0=A0=A0=A0=A0=A0mdadm --grow /dev/md0 --raid-devices=3D16 > =A0=A0=A0=A0=A0=A0=A0=A0mdadm: Need to backup 93184K of critical section.. > =A0=A0=A0=A0=A0=A0=A0=A0mdadm: Cannot set device shape for /dev/md0: Devi= ce or resource busy > =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0Bitmap must be removed befor= e shape can be changed >=20 > Now, the docs (and indeed several websites when I googled) suggest that y= ou can have a bitmap present on a grow, and the help suggests that you can = even change it during a grow.. >=20 >=20 > =A0=A0=A0=A0=A0=A0=A0=A0=A0If the word internal is given, then the bitmap= is stored with the metadata on the array, and so is replicated on all devi= ces.=A0 If the word none is given with --grow mode, then any bitmap that is= present is removed. >=20 >=20 > Is there an issue with the array, or just in my understanding and google = foo? You cannot reshape an array while it has a bitmap attached. This restriction will probably be removed in Linux 3.5 NeilBrown >=20 > I am running on Centos 6 (2.6.32-220.7.1.el6.x86_64) with madam (mdadm - = v3.2.2 - 17th June 2011) >=20 >=20 > Thanks again. >=20 >=20 >=20 > =A0 > ----- Original Message ----- > From: NeilBrown > To: jahammonds prost > Cc: Linux RAID > Sent: Wednesday, 11 April 2012, 0:43 > Subject: Re: Failed Array Rebuild advice Please >=20 > On Tue, 10 Apr 2012 21:14:07 -0700 (PDT) jahammonds prost > wrote: >=20 > > One other question as the badblocks progresses. > > =A0 > > >=A0 It will then recovery both devices in parallel. > >=20 > > How many additional devices can be done at the same time? I presume tha= t I am going to have to=A0replace the 2 failed devices before I try and gro= w the array by adding 3 additional drives? I so, how many=A0additional driv= es can be rebuilt concurrently with a grow? Could I add 5 devices and not s= ee too much of a performance hit? Or would it be more sensible to add them = one at a time? > >=20 >=20 > I think it is best to recover, and then reshape later.=A0 I cannot promis= e that > doing them both at once will work .... it might but I have a feeling that > there might be problems. >=20 > Adding three additional drives at once should work well enough in terms of > performance. > However I would only do it if I were very very confident of the drives. > If you hit bad blocks you start losing drives, and if you have 3 drives t= hat > you haven't used before, the chance of losing them all during the reshape= - > while still small - becomes a little too high for comfort. >=20 > But if you have run heavy bad-blocks tests on them all and they appear to > work, then adding 3 drives at once should be fine. >=20 > NeilBrown --Sig_/kdAosdFUTjZrL=rpq1fQQe6 Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBT4Y9Mznsnt1WYoG5AQKMww/7BlNaGhBSUsLgRKBYwcMW9i0+jlqkq88V HCzrU7wTmoR/kX+3xKZnwaBpfjyI79b1/0c4v8xhH1qx5Y9oxWDyCHbrTX9df+9c aR7cftCEwAeBiBpjzSl5Oh3sebpP2ggUKcz/nHHcA1J40AL48wxPKVenFbw3VU+F Xpb4hl38ae7m74dEOdr7jmss4iaFcl73iMJlEmY1KpP74e7KWkyDnZkSOHWsXUvu IbROAtKOOlJCDynZ0MBHXRot9BdxGLGp4fFrRoo74eTFJheeHFhdfTKEpZUgqLow MEb2/WIVduXIYp6j0WrpJihgwV4y8U3KKR9bWxfhNm8RCh5TEa/iKwyFrqzOyB9r 1ZMcVXIChHvZUlqEVC9MY9Hm4PWmhpwYnIOrh5mkYyFeBqNzJZGSEcark9xy1jJJ g5pjSmnQR8w6MWxeOOScJmcUwzh1rIVFRKc9IbKNkoTxgsX+DEGVapNI0KBbAGQE 1xn9Wq34rKGP5lCM3rz2M1Pk4OYacp3g19FOnL8hRdvSgwX5Nfnp0JqtLDWPxQCU Zqek1Tx1wGAB5qI11nznwZFB+62n6eHCa+nluVA2njMFT068J5+24O1Lpfz0/PNl uOMaSbuwG1g5XDCsxPjPBq9FN1dSTyLf2/14mKrmaAS/ziPqhGnkLWrkjlY+RTYS hlat+WEFOKY= =DfGW -----END PGP SIGNATURE----- --Sig_/kdAosdFUTjZrL=rpq1fQQe6--