On Fri, Feb 27, 2015 at 10:07 PM, Mike Wright
<nobody(a)nospam.hostisimo.com> wrote:
I'd like to see it stay open. The OP was not trolling and is obviously in
desperate need of a solution. I'm sure every one of us has lost critical
data at one time or another.
I suggested closing this thread mainly because there were already a
bunch of replies on the centos list and seemed the best place to carry
on the discussion rather than fragmenting it.
I went ahead and tried to replicate the conditions (idealistically) in
a VM, with XFS, ext4, and Btrfs and simulated the failure.
tl;dr Btrfs faired the best by far permitting all data on surviving
drives to be copied off; the ext4 fs imploded at the first ls command
and nothing could be copied so it's a scrape operation, and XFS copied
~1/7 of the data, even though 3/4 of the drives were working.
The main solution, I think, in the LVM dead PV case is this command:
# vgchange -a y --activationmode partial
This makes the LV active with the PV missing. The least amount of
change in a case like this, the better, in order to avoid user induced
data loss (really, really common), so I don't recommend removing or
replacing the dead PV. If the LV type were mirror (legacy) or raid1,
then it would be a different story altogether.
Details are in the CentOS thread I previously included the URL for.
LVM is still considered arcane by many and any shared wisdom
regarding OP's
situation would accrue greatly to our cumulative knowledge base.
Quite.
I can attest that I once lost a volume that was so important to me
that I
got sick to my stomach. I am loathe to wish that upon anyone.
Backups!
--
Chris Murphy