From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Hardcastle Subject: Re: sdc1 does not have a valid v0.90 superblock, not importing! Date: Wed, 11 Aug 2010 08:30:31 -0700 (PDT) Message-ID: <282617.15518.qm@web51308.mail.re2.yahoo.com> References: <20100811213405.09a0b709@notabene> Reply-To: Jon@eHardcastle.com Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20100811213405.09a0b709@notabene> Sender: linux-raid-owner@vger.kernel.org To: Jon@eHardcastle.com, Neil Brown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --- On Wed, 11/8/10, Neil Brown wrote: > From: Neil Brown > Subject: Re: sdc1 does not have a valid v0.90 superblock, not import= ing! > To: Jon@eHardcastle.com > Cc: jd_hardcastle@yahoo.com, linux-raid@vger.kernel.org > Date: Wednesday, 11 August, 2010, 12:34 > On Wed, 11 Aug 2010 04:19:07 -0700 > (PDT) > Jon Hardcastle > wrote: >=20 > >=20 > > --- On Wed, 11/8/10, Neil Brown > wrote: > >=20 > > > From: Neil Brown > > > Subject: Re:=A0 sdc1 does not have a valid > v0.90 superblock, not importing! > > > To: Jon@eHardcastle.com > > > Cc: jd_hardcastle@yahoo.com, > linux-raid@vger.kernel.org > > > Date: Wednesday, 11 August, 2010, 12:06 > > > On Wed, 11 Aug 2010 02:55:44 -0700 > > > (PDT) > > > Jon Hardcastle > > > wrote: > > >=20 > > > > (my first attempt appears to have been > bounced as the > > > spam checker thought it had HTML in it?!) > > >=20 > > > odd... came through ok for me the first time. > > >=20 > > > >=20 > > > > Help! > > > >=20 > > > > Long story short - I was watching a movie > off my RAID6 > > > array. Got a smart error warning > > >=20 > > > > Aug 10 22:00:07 mangalore kernel: raid5: > cannot start > > > dirty degraded array for md4 > > >=20 > > > This is the current problem.=A0 The array is dirty > and > > > degraded so there could > > > theoretically be undetectable corruption.=A0 > Chance is > > > quite low but it is > > > there so md won't start with out you > acknowledging the risk > > > by giving the > > > --force flag to mdadm --assemble. > > > Only do that if you are confident that your > hardware is > > > working correctly. > >=20 > > Well I am reasonable sure the controller came adrift > the first time.. when i reseated it i stopped getting 100's > of errors.. and it has survived 1.5 badblocks checks. It is > being held in place by one of those bars you press down > (does all the expansion cards in 1 go) except i dont think > it is very good. I will screw it down. > >=20 > > >=20 > > > > It appears sdc has an invalid superblock? > > > >=20 > > > > This is the 'examine' from sdc1 (note the > checksum) > > > >=20 > > > > /dev/sdc1: > > > ..... > > > >=A0 =A0 =A0=A0=A0Checksum : b335b4e3 - > > > expected b735b4e3 > > >=20 > > > Single bit error.=A0 That isn't good as it means > some > > > bit of memory or some bit > > > on some bus somewhere cannot be trusted. > > > It could be a transient thing and will never > happen > > > again.=A0 Or maybe not. > > > Given the smart errors and the fact that you have > had > > > problems with the drive > > > before it seem very likely that the problem is in > that > > > drive.=A0 I suggest > > > unplugging it and leaving it unplugged.=A0 Some > memory > > > buffer in the drive is > > > probably marginal.=A0 I don't think they use ECC > > > memory. > >=20 > > Could this be a result of me forcing a power off when > the drive was causing problems? >=20 > Probably not.=A0 Forcing a power off may well have left > the array 'dirty' so > that it wouldn't assemble, but is fairly unlikely to > corrupt data within a > block. >=20 > >=20 > > What are the dangers to removing it, zeroing the > superblock and readding? is it MORE dangerous than leaving a > raid 6 degraded for a few days? >=20 > In general, I would say the chance of a known-bad drive > causing problems is > greater than the chance of a fewer known-good drives > causing problems. > But then you seem to think it isn't the drive, it was the > controller and that > is fixed... >=20 > This is really about your level of trust in the hardware. > If you trust sdc as much as the others, include it in the > array. > If you don't, then don't. >=20 > NeilBrown >=20 >=20 >=20 > >=20 > > >=20 > > > >=20 > > > > Anyways... I am ASSUMING mdadm has not > assembled the > > > array to be on the safe side? i have not done > anything.. no > > > force... no assume clean.. I wanted to be sure? > > >=20 > > > You assume correctly. > > >=20 > > > >=20 > > > > Should i remove sdc1 from the array? It > should then > > > assemble? I have 2 spare drives that I am getting > around to > > > using to replace this drive and the other 500GB.. > so should > > > I remove sdc1... and try and re-add or just put > the new > > > drive in? > > > >=20 > > > > atm I have 'stop'ped the array and got > badblocks > > > running.... > > > >=20 > > >=20 > > > Remove sdc and assemble the array with --force, > and get a > > > new device to > > > replace /dev/sdc as soon as possible. > >=20 > > Thanks Neil - I panic'd as previously it has mounted > the array in a degraded state... but previously the drive > has disappeared completely... whereas in this case it is > present... but wrong! > >=20 > > >=20 > > > NeilBrown > > > -- > > > 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=A0 http://vger.kernel.org/majordomo-info.h= tml > > >=20 > >=20 > >=20 > >=A0 =A0 =A0=A0=A0 =46or the benefit of those that follow! I assemble the array by specify= ing exactly the drives I wanted in it.. once assembled i could confiden= tly zero-block the troublesome drive... without it rearing its ugly hea= d again! I now have a 1 drive down - degraded raid 6 array. =20 -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html