Re: Failed RAID-5 with 4 disks

On Sat, Sep 17, 2005 at 11:31:12AM +0200, Burkhard Carstens wrote:

Am Freitag, 16. September 2005 21:09 schrieb Frank Blendinger:

quoted

On Fri, Sep 16, 2005 at 10:02:13AM -0700, Mike Hardy wrote:

quoted

Frank Blendinger wrote:

quoted

This is what I did so far: I got one of the two bad drives (the
one that failed first) replaced with a new one. I copied the
other bad drive to the new one with dd. I guess that not
everything could be copied alright, I got 10 "Buffer I/O error on
device hdg, logical sector ..." and about 35 "end_request: I/O
error, hdg, sector ..." error messages in my syslog.

I am unable to find the beginning of this thread, so please excuse me if 
this has already been said, but:

You did use ddrescue, didn't you? Because dd, when it fails to read a 
block, it won't write that block. That's why your superblock might have 
"moved" about 45 sectors towards the beginning of the drive.
ddrescue writes a block with zeros when reading that block fails, so 
every readable sector get copdied to its corresponding sector on the 
new drive..

OK, thanks for the note, I am going to do a bad block scan with smart
and then try again with ddrescue. I hope this will restore the
superblock.


Greets,
Frank