Goswin von Brederlow wrote:
LCID Fire <lcid-fire@xxxxxxx> writes:
On my raid10 array (4 drives) I've had 2 drives (the same model) which
got disconnected by the kernel (almost at the same time). It seems
like both were one raid1 part so one half of the raid0 is missing.
Afterwards I tried to readd the drives again (my bad) so now I'm stuck
with 1 half of the raid0 part being present and valid and the other (2
drives) marked as spare.
The thing I'd like to do is:
- Take 2 new drives (different manufacturers)
- Clone one of the valid and one of the spare drives to the new drives
- Try to reassemble the array.
Problem is - is this even possible?
How do I tell mdadm to not care about the spare state?
Does the kernel write bogus data to the still valid drives if the
other 2 fail?
Would be great if someone could enlighten me ;)
P.S.: Does someone know how to easily report the different sata errors
which the kernel encounters?
mdadm --create --assume-clean -l 10 -n 4 /dev/mdX /dev/copied_disk_1 /dev/copied_disk2 missing missing
You need to match the create parameters exactly with the ones you
initially used (near/offset/farcopies? stripe size? ...) and the order
of devices is relevant so you might have to shuffle the disk
arguments. So just try different orders till the result can be mounted
or fscked. With the wrong options the mount/fsck could screw up the
data but then you copy the disk again for the next try. It should be
reasonably obvious when mount/fsck goes wrong as it should find tons
of errors. Mostly I would expect mount/fsck to just fail with the
wrong mdadm args though.
May I say that this makes a great case for saving the contents of some
files to a safe place when the system is up and running right.? Maybe
all of /etc, and at least a "tree /sys" and /proc/mdstat would be
useful, preferably on something readable like a CD or USB flash drive,
so you have a chance of reading it if you can't boot.
Of course a rescue flash drive is pretty useful as well, so that's
probably the way to go.
--
bill davidsen <davidsen@xxxxxxx>
CTO TMR Associates, Inc
"You are disgraced professional losers. And by the way, give us our money back."
- Representative Earl Pomeroy, Democrat of North Dakota
on the A.I.G. executives who were paid bonuses after a federal bailout.
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