[aklug] Re: Need help repairing an Ubuntu raid 5 array

Sounds like I gave you a bum route. Sorry I was concentrating on getting =
into the file system=85.

Jim MacDonald
jim@macdonald.org

On Dec 28, 2009, at 1:19 AM, Peter Michael wrote:

> Clay,
> Just for information
> In general fsck should NEVER be run to fix disk errors in a Raid 5 =
array..because .RAID-5 arrays do not contain a file
> system that fsck can read,so you
> cannot use fsck to do preliminary checking and/or repair; you must
> use ckraid=20
> The ckraid command can be safely run without the --fix option=20
> to verify the inactive RAID array without making any changes.=20
> When you are comfortable with the proposed changes, supply=20
> the --fix option.=20
> If you wish, you can try designating one of the disks as a ''failed
> disk''. Do this with the --suggest-failed-disk-mask flag.=20
> Only one bit should be set in the flag: RAID-5 cannot recover two=20
> failed disks.
> The mask is a binary bit mask: thus:=20
> 0x1 =3D=3D first disk
> 0x2 =3D=3D second disk
> 0x4 =3D=3D third disk
> 0x8 =3D=3D fourth disk, etc.
> Some other tidbits learned at big blues disk recovery school are ---
> If two drives in an array have bad sectors, then the array will not =
function properly even after a repair,=20
> In fact it is very seldom the array will actually rebuild if it does =
however it will soon error out and you will be back where you started,=20=

> The recommended procedure on dual disks in a raid 5 array having =
sector errors is Replacement of both drives and recovering your data =
from back up to the devices
> You might also consider defining an additional drive as a hot spare in =
the array, doing this will in the future allow failover of a disk to the =
hot spare sparing you the problems you now have.
> hope this helps a bit
>=20
> Pete
>=20
>=20
>=20
>=20
>=20
>=20
>=20
> ________________________________
> From: CLAY SCOTT <rudeboy@gci.net>
> To: aklug@aklug.org
> Sent: Sat, December 26, 2009 11:52:24 PM
> Subject: [aklug] Re: Need help repairing an Ubuntu raid 5 array
>=20
> The boot process drops into a maintenance shell, but I can't fsck the =
drives. the array consists of sdb1 through sdf1 and fsck at first =
reported they were busy, then in the maintenance shell said they were =
available, but saw them as raid drives and complained that it couldn't =
find e2fsck.mdraid.
>=20
> now in the livecd the disk monitoring application (which I clearly =
overlooked installing before) is showing bad sectors on sdc and sde. i'm =
running tests on them now.
>=20
> If they can't be repaired I guess I'm looking at having to source some =
500GB drives to get the array repaired so I can back it up. Pretty =
coincidental really considering I was looking to upgrade the array in a =
few weeks.
>=20
> I'll let you know how the tests turn out.
>=20
> ~Clay=20
>=20
> ----- Original Message -----
> From: Jim MacDonald <jim@macdonald.org>
> Date: Saturday, December 26, 2009 9:22 pm
> Subject: [aklug] Re: Need help repairing an Ubuntu raid 5 array
> To: CLAY SCOTT <rudeboy@gci.net>
> Cc: aklug@aklug.org
>=20
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA1
>>=20
>> Have you tried booting from a LiveCD to see if you can FSCK /dev/md0?
>>=20
>>=20
>> CLAY SCOTT wrote:
>>> My Ubutnu fileserver recently suffered a power failure and I=20
>> haven't been able to get the raid5 array working since. I have been=20=

>> meaning to get it on a basic smart UPS that will shut it down=20
>> during a blackout, but it looks like i dragged my feet too long.
>>>=20
>>> The boot process drops to the maintenance shell when it can't=20
>> mount /dev/md0, but i'm not able to reassemble the array, check it,=20=

>> activate it or anything. I'm getting more and more out of practice=20
>> as my life transitions more toward work and family life.
>>>=20
>>> I normally have hockey on Friday nights, but I was hoping there=20
>> was a raid guru out there who could help me get it working again if=20=

>> I were to bring my fileserver down to FNL.
>>>=20
>>> I'm sure it's something stupid and simple I'm overlooking, but=20
>> it's driving me nuts. Let me know if anyone is interested in=20
>> lending a hand.
>>>=20
>>> ~Clay
>>> ---------
>>> To unsubscribe, send email to <aklug-request@aklug.org>
>>> with 'unsubscribe' in the message body.
>>>=20
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>> ---------
>> To unsubscribe, send email to <aklug-request@aklug.org>
>> with 'unsubscribe' in the message body.
>>=20
>>=20
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>=20
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>=20

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Received on Mon Dec 28 17:04:08 2009