Den 2023-09-23 kl. 13:24, skrev Roman Mamedov:
On Sat, 23 Sep 2023 12:54:52 +0200
Joel Parthemore <joel@xxxxxxxxxxxxxxx> wrote:
the RAID array looking seemingly okay (according to mdadm -D) BUT this
time, any attempt to access the RAID array or even just stop the array
(mdadm --stop /dev/md126, mdadm --stop /dev/md127) once it was started
would cause the RAID array to lock up. That means (I think) that I can't
create an image of the array contents using dd, which is what -- of
course -- I should have done in the first place. (I could assemble the
RAID array read-only, but the RAID array is out of sync because it
didn't shut down properly.)
Does accessing the array also lock up when it's assembled read-only?
I didn't want to try that again until I had confirmation that the
out-of-sync wouldn't (or shouldn't) be an issue. (I had tried it once
before, but the system had somehow swapped /dev/md126 and /dev/md127 so
that /dev/md126 became the container and /dev/md127 the RAID-5 array,
which confused me. So I stopped experimenting further until I had a
chance to write to the list.)
The array is assembled read only, and this time both /dev/md126 and
/dev/md127 are looking like I expect them to. I started dd to make a
backup image using dd if=/dev/md126 of=/dev/sdc bs=64K
conv=noerror,sync. (The EXT4 file store on the 2TB RAID-5 array is about
900GB full.) At first, it was running most of the time and just
occasionally in uninterruptible sleep, but the periods of
uninterruptible sleep quickly started getting longer. Now it seems to be
spending most but not quite all of its time in uninterruptible sleep. Is
this some kind of race condition? Anyway, I'll leave it running
overnight to see if it completes.
Accessing the RAID array definitely isn't locking things up this time. I
can go in and look at the partition table, for example, no problem.
Access is awfully slow, but I assume that's because of whatever dd is or
isn't doing.
By the way, I'm using kernel 6.5.3, which isn't the latest (that would
be 6.5.5) but is close.
Thanks for the help,
Joel Parthemore
