Hi All,

After a crash, probably caused by some raid issue, the array can't be 
assembled again. It looks like 8 disk were disappearing form the raid at 
the same time, which then lead to the system crash. Now I'm unable to 
get the array back to live again. Because the whole system was on the 
failing array, I can't access any additional information to check what 
happened. The system is a 8 year old SUN Fire X4540 system running under 
Ubuntu 12.04.5 (kernel-3.13.0-91 and mdadm-3.2.5-1ubuntu0.3), which is 
mainly used for data conversion (converting very large files from one 
format into another). The boot partition is placed on a 2GB ssd and the 
rest is running on the 48disk raid6 array. I have booted the system from 
a usb stick with clonezilla (kernel 4.4.x + mdadm 3.3) and started 
digging...

Since this is the first time, that a I face such a large array and such 
an issue, I better follow the advice from the Linux-Raid-Wiki and 
request for help.

As one can see in the attached log, the 'Events' count of 40 drives is 
4391 and 4385 for the 8 others. We have the same picture for the 
'State', 40 drives state 'clean' and 8 drives 'active'. So I tried 
'mdadm --assemble --force ...'.  This fixed the event count and faulty 
flag on 4 of the 8 disks. But still the array can't be created.

Except one smart error (1 Currently unreadable (pending) sectors) do all 
other drives pass the extended smart test. I know, this does not mean 
that the drives are not damaged or broken.

Anyway, how should I process to get the array working again?
-- 
Thanks and regards,
Soeren