I am not convinced this is a drive failure (yet). You have
sdh,sdi,sdj,sdk,sdl,sdm all reporting errors or error recovery.
This sounds like a physical backplane failure (is this on an expander
system? we have seen this/had this happen before), a cable to the SATA
card failing (we have seen this/had this happen before), or a power
supply issue (can't handle all the drives in constant operation, which
we have seen before as well).
Driver issues are possible, but it is pursuing normal failure code
paths, so unless the driver is tickling the remove code on its own ...
Smart could be offlining the drive, and having it non-responsive.
Something else could be doing that as well (vibration, power quality, ...)
What does
hdparm -I /dev/sdh
tell us?
If nothing, we need to use sdparm to get some information.
