From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: Converting from Raid 5 to 6 Date: Tue, 3 Dec 2013 07:38:09 +1100 Message-ID: <20131203073809.3238b7e4@notabene.brown> References: <20111025071443.4c497656@notabene.brown> <20111025073908.6d754588@notabene.brown> <20131202165127.0fe2dd5f@notabene.brown> <2042216353575894098@unknownmsgid> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/QVZor3yjGpFJkbAY3O3s=SY"; protocol="application/pgp-signature" Return-path: In-Reply-To: <2042216353575894098@unknownmsgid> Sender: linux-raid-owner@vger.kernel.org To: Michael Busby Cc: "linux-raid@vger.kernel.org" List-Id: linux-raid.ids --Sig_/QVZor3yjGpFJkbAY3O3s=SY Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Mon, 2 Dec 2013 15:07:57 +0000 Michael Busby wrote: > Using -f seems to have worked just running e2fsck now Excellent. >=20 > When running a command like mdadm --assemble -- force --verbose > /dev/md0 /dev/sa[abcde] how important it the drive order? Not at all. The order is only important for --create. NeilBrown >=20 >=20 > Sent from my iPad >=20 > > On 2 Dec 2013, at 05:51 am, NeilBrown wrote: > > > > On Sat, 30 Nov 2013 22:13:58 +0000 Michael Busby > > wrote: > > > >> Sorry to bring up a old thread, last night i had a power cut and this > >> morning when the power has come back i have tried to boot the server, > >> but the raid will not assemble on using a live CD i have found that > >> one of the disk is reporting "possibly out of date" is there any way > >> to force this disk back in? the bigger problem i have is that my > >> external caddie has died so i was running a degraded raid 6 but now it > >> is only starting with 4 out of 6 devices. is there anyway to get this > >> back? > > > > It's really hard to know what is possible without precise details. > > Output of "mdadm -E" for each member device is always a good idea. > > If you are having trouble assembling, then output of the assemble comma= nd > > with -vv added never goes astray. > > Have you tried adding "-f" to the assemble command. Often helps and is > > unlikely to hurt. > > > >> > >> i have though about recreating the array using the --assume-clean > >> option but not sure if that's a good idea > > > > Not a good idea except as a very last resort. > > > > NeilBrown > > > > > >> > >> any help will be much appreciated > >> > >> > >> > >>> On 24 October 2011 21:47, Michael Busby w= rote: > >>> > >>> I was sure i added the device before, but when rebooted the system it > >>> has seemed to lose the extra drive and i had already restarted the > >>> grow command with out checking the disk was there, so more than likely > >>> a mistake by me > >>> > >>> > >>> > >>>> On 24 October 2011 21:39, NeilBrown wrote: > >>>> On Mon, 24 Oct 2011 21:19:22 +0100 Michael Busby > >>>> wrote: > >>>> > >>>>> Ok thanks, i have 1 small issue, when added the extra disk its been > >>>>> maked as spare, is this normal? > >>>>> > >>>>> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] > >>>>> [raid4] [raid10] > >>>>> md0 : active raid6 sde[0] sdg[6](S) sda[4] sdb[3] sdd[2] sdc[1] > >>>>> 7814055936 blocks super 1.0 level 6, 512k chunk, algorithm 18 > >>>>> [6/5] [UUUUU_] > >>>>> [>....................] reshape =3D 3.0% (59244544/195351398= 4) > >>>>> finish=3D11122.8min speed=3D2837K/sec > >>>> > >>>> It looks like the extra drive was added after you started the grow. > >>>> > >>>> So it is still a spare. > >>>> Once the grow finishes you will have a singly-degraded RAID6. > >>>> Then it will immediately start recovering the missing device to the = spare. > >>>> > >>>> Did you add the extra drive after starting the grow - or before?? > >>>> > >>>> NeilBrown > >>> > >>> > >>>> > >>>>> > >>>>> > >>>>> > >>>>>> On 24 October 2011 21:14, NeilBrown wrote: > >>>>>> On Mon, 24 Oct 2011 17:03:46 +0100 Michael Busby > >>>>>> wrote: > >>>>>> > >>>>>>> should the speed be very slow when doing this progress, its a lot > >>>>>>> slower than a normal grow > >>>>>> > >>>>>> Yes. > >>>>>> The array is being reshaped in-place. i.e. data is being read fro= m part of > >>>>>> the array, rearranged, and written back to the same part of the ar= ray. > >>>>>> As you can imagine, this is risky - a crash will leave an inconsis= tent state. > >>>>>> Hence the backup file. Everything in the array is first written t= o the > >>>>>> backup file, then back to the array. So it is slow. > >>>>>> > >>>>>> A "normal" grow is writing to somewhere where there is no valid da= ta, so it > >>>>>> doesn't need the backup. > >>>>>> > >>>>>> I do have a plan to make this faster.... but I have lots of plans = and little > >>>>>> time. > >>>>>> > >>>>>> NeilBrown > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>>> > >>>>>>> reshape =3D 1.2% (25006080/1953513984) finish=3D12481.8min speed= =3D2574K/sec > >>>>>>> > >>>>>>>> On 24 October 2011 15:11, Mathias Bur=C3=A9n wrote: > >>>>>>>>> On 24 October 2011 14:11, Michael Busby wrote: > >>>>>>>>> At the moment i have a raid5 setup with 5 disks, i am looking t= o add a > >>>>>>>>> 6th disk and change from raid 5 to raid 6 > >>>>>>>>> > >>>>>>>>> having looked at Neil's site i have found the following command= , and > >>>>>>>>> just want to double check this is still the recommend way of > >>>>>>>>> converting > >>>>>>>>> > >>>>>>>>> mdadm --grow /dev/md0 --level=3D6 --raid-disks=3D6 --backup-fil= e=3D/home/md.backup > >>>>>>>>> > >>>>>>>>> also would i need to add the extra disk before or after the com= mand? > >>>>>>>>> > >>>>>>>>> cheers > >>>>>>>>> -- > >>>>>>>>> To unsubscribe from this list: send the line "unsubscribe linux= -raid" in > >>>>>>>>> the body of a message to majordomo@vger.kernel.org > >>>>>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.h= tml > >>>>>>>> > >>>>>>>> Hi, > >>>>>>>> > >>>>>>>> I grew my 6 disk RAID5 to a 7 disk RAID6. First, add the drive. = Then > >>>>>>>> partition it as required. Then add the drive to the array (I thi= nk > >>>>>>>> it'll become a spare?). Then you can grow it. > >>>>>>>> > >>>>>>>> Make sure you're using the latest mdadm tools available. > >>>>>>>> > >>>>>>>> Regards, > >>>>>>>> Mathias > >>>>>>> -- > >>>>>>> To unsubscribe from this list: send the line "unsubscribe linux-r= aid" in > >>>>>>> the body of a message to majordomo@vger.kernel.org > >>>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html > > --Sig_/QVZor3yjGpFJkbAY3O3s=SY Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIVAwUBUpzvsTnsnt1WYoG5AQKf1RAAmPfrTqIpLmGpa7oPFnjra2onEJqwSiSV B/x6kDMmaMmzd8inJEHghTFcuCTkRf+Jy+f7Oo3fXDaRsZPD1Yc0iGfp2nh8y1GM STcs8owyg6sQGMsLp5zji7XwtFyMgs1M5cUtozSz4ofaWn7KjQKBzH3I+UMxnQwR Amea//dFaUQbY7GwANAsSAq2NxXkS8thk4wl80GAH/xPd3+SuqQlVlyaCTtE3Mpy 10lewel+95QuwDPRZACkH7aHArycz6CAH0p5VNXwllzKBg0aJZGF8Jr0IWC4ib7U RZuFm+rMSpCDCMQNfdrd0wS8CsNOdQheCN9MkfNiPZndigED0t8LjTSbOpWxF3Ae p1ClHyva4ZpscY1rPSxf7DSQ1grM2OvOE18m9so6tX8XCUP5ZmmXSL+a0uZrPuIa yQPPWdbgehf1aEkZbiQEcrQLRMQ6gMHLPcLfWKdCBqWLPodcY42PQrO6GdsCT7M5 0C4DJy8obYj477urYzauBxeGnHRxAIUuFDasms4JzH/zKqTOSRn426ae48LLjy3L 0FdvMy2yy9muzvfKvBDUF40YLfdGsXNGSyjKr/kqTsBxe4/UGOPoyubtVave9gsb OjHpUKMSsD0tUiJk7ZPv9lfhWbd3SByqwdngrnYw1E/lg6587CNt4pO+5xinckk9 1W0SyHalM0s= =pU8F -----END PGP SIGNATURE----- --Sig_/QVZor3yjGpFJkbAY3O3s=SY--