Re: What just happened to my disks/RAID5 array?

[Johannes Truschnigg <johannes@truschnigg.info>]

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On Fri, Jan 06, 2012 at 09:51:32AM -0500, Phil Turmel wrote:
> [...]
> https://lkml.org/lkml/2012/1/5/76
> 
> Note that it involves ext4 and LVM snapshots, so may not apply to you.  But the
> bug hasn't been clearly identified, so my paranoid approach to kernels would
> keep me off of it. (On production systems, of course.  I regularly run -rc
> kernels on my laptop.)

I arrived at the same conclusion, and decided to stick with 3.2.0 for now.

> [...]
> You would need them if you ever ran into some catastrophic problem where
> "--create --assume-clean" was needed.

Thanks, I will keep that information in a secure place then.

> [...]
> Actually, given the /proc/mdstat contents you reported, you might be able to just
> do "mdadm --run /dev/md0"

Probably, yes. I stopped the array, --assemble --force'd it, and everything
was up again. The LVM metadata proved consistent, and a read-only fsck of the
filesystem on top of the only LV defined on the array told me that there were
some (very) minor fs inconsistencies. They were corrected by a secind fsck
run, and everything seems perfectly fine again :) I don't keep checksums of
the inodes' data, but I tested with a bunch of archives stored in the fs, and
there were no CRC errors or the like to be found.

> The output will change substantially, as it attempts to map the entire
> storage tree, reporting all serials, uuids, and labels, along with other
> useful information.  I have a future number of enhancements in mind, but
> it's a spare-time project.  I'm glad you like it, though.

I noticed it did, yes - it's even more nifty than I thought ;) I noticed that
it would die with an uncaught exception (sorry, I had noted it down in a file
in /tmp, but I involuntarily lost it upon rebooting) if you had an LVM VG/LV
showing up in `lvs` that wasn't "active"/had no corresponding device nodes in
/dev; you may want to look into that some time.

> You don't need the report for this incident, though.  Just stick it with your
> backups.  And make a new one any time you change your setup.

Will do. Thanks again for your guidance and support! Have a nice day!

-- 
with best regards:
- Johannes Truschnigg ( johannes@truschnigg.info )

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