Re: Need urgent help in fixing raid5 array

[Mike Myers <mikesm559@yahoo.com>]

BTW, several of the disks that md didn't want to assemble have perfectly valid uuid info on them.  if I try and manually specify the devices in the --assemble line, and add the ones that are missing (but have a valid uuid for the array), even with the force option, md refuses to assemble them.  The disks can't be all bad can they?  That's 4 drives out of 14 that would have all had to go bad at once. 

thx
Mike




----- Original Message ----
From: Justin Piszcz <jpiszcz@lucidpixels.com>
To: Mike Myers <mikesm559@yahoo.com>
Cc: linux-raid@vger.kernel.org; john lists <john4lists@gmail.com>
Sent: Friday, January 2, 2009 10:57:13 AM
Subject: Re: Need urgent help in fixing raid5 array



On Fri, 2 Jan 2009, Mike Myers wrote:

> Well, I can read from sdg1 just fine.  It seems to work ok, at least for a few GB of data.   I'll try this on some of the other disks, but it is possible for to pull the disks out of the backplane and run the SFF-8087 fanout cables direct to each drive and bypass the backplane completely.  It certainly would be easy to do this for the at least the sdo1 drive and see if I can get better results going direct to the disk.  I have moved the disks around the backplane a bit to deal with the issues of the controller failure, so I am pretty sure it's not just one bad slot or the like.
> 
> So you've seen a backplane fail in away that the disks come up fine at boot but have corrupted data transfers across them?  I wonder about the sata cables in that case as well.  I could hook up a pair of PMP's to my SI3132's and bypass the 8077 cables as well.

1. Try by-passing the backplane.
2. Bad cables will usually cause smart identifier UDMA_CRC_Error_Count to
   increase quite high, if it is 0 or close to it, the cable is unlikely the
   issue.
3. I have seem all kinds of weirdness with bad backplanes, drives dropping out
   of the array, drives producing I/O errors, etc.

Justin.

--
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.html