Re: RAID 0 went down...

[Romeyn Prescott <romeyn@gmail.com>]

Thanks for the advice.

Actually, after I posted I did some more Googling and discovered
mdadm, which didn't appear to be included with RH 9.0.  I installed it
and was able to use the -A option with the -f (force) command ti get
the RAID back up and mounted.  I have copied just about all of the
data off of it!

As I look over this some more (I'm no RAID expert) it seems to me that
if I could just somehow re-synchronize the "superblock update times"
that md0 would get automatically recreated at boot instead of failing
out.  Is there any way to do that?  When I forced the mount, I checked
the logs and the filesystem has been flagged for an fsck, but that'll
never happen if md0 isn't reconstituted at boot!

TIA,
...ROMeyn


On Mon, 11 Oct 2004 05:10:40 -0500, Mike Tran <mhtran@us.ibm.com> wrote:
> Hi Romeyn,
> 
> If there were I/O errors on one of the disks, I am not sure that you
> want to re-assemble/re-create this "corrupted" raid0 array.  However, if
> you just want to get some data out of the volume /dev/md0, you can use
> mdadm to re-create the array:
> 
> mdmadm -C -R /dev/md0 -c 64 -l 0 -n 2 /dev/sdb1 /dev/sdc1
> 
> Regards,
> Mike T.
> 
> 
> 
> On Mon, 2004-10-11 at 07:28, Romeyn Prescott wrote:
> > I have a RH 9.0 box with a RAID 0.  I started getting some I/O errors
> > and when I rebooted the box md0 wouldn't mount.
> >
> > /etc/raiddtab:
> > -----
> > raiddev             /dev/md0
> > raid-level                  0
> > nr-raid-disks               2
> > chunk-size                  64k
> > persistent-superblock       1
> > nr-spare-disks              0
> >     device          /dev/sdb1
> >     raid-disk     0
> >     device          /dev/sdc1
> >     raid-disk     1
> > -----
> >
> > The problem appears to be with /dev/sdc, yet it passes all of the
> > manufacturer's (Seagate) diagnostics.  Here's what /var/log/dmesg
> > says:
> > -----
> > md: Autodetecting RAID arrays.
> >  [events: 00000095]
> >  [events: 00000031]
> > md: autorun ...
> > md: considering sdc1 ...
> > md:  adding sdc1 ...
> > md:  adding sdb1 ...
> > md: created md0
> > md: bind<sdb1,1>
> > md: bind<sdc1,2>
> > md: running: <sdc1><sdb1>
> > md: sdc1's event counter: 00000031
> > md: sdb1's event counter: 00000095
> > md: superblock update time inconsistency -- using the most recent one
> > md: freshest: sdb1
> > md: kicking non-fresh sdc1 from array!
> > md: unbind<sdc1,1>
> > md: export_rdev(sdc1)
> > md0: former device sdc1 is unavailable, removing from array!
> > md0: max total readahead window set to 512k
> > md0: 2 data-disks, max readahead per data-disk: 256k
> > md: md0, array needs 2 disks, has 1, aborting.
> > raid0: disks are not ordered, aborting!
> > md: pers->run() failed ...
> > md :do_md_run() returned -22
> > md: md0 stopped.
> > md: unbind<sdb1,0>
> > md: export_rdev(sdb1)
> > md: ... autorun DONE.
> > -----
> >
> > Is there any way I can recover from this?  I've been googling my
> > brains out, but most of what I find relates to RAID1.  Restoring from
> > a backup is possible, but..."complicated" and is my last resort.
> >
> > TIA,
> > ...ROMeyn
> 
> -
> 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
> 


-- 
http://www2.potsdam.edu/prescor/signat-url.htm