The controller hasn't realized it yet (no check-raid errors) but:
[798900.159707] sd 0:2:10:0: [sdk] Unhandled error code
[798900.159711] sd 0:2:10:0: [sdk] Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK
[798900.159715] sd 0:2:10:0: [sdk] CDB: Read(10): 28 00 3e 3d 58 80 00 00 08 00
[798900.159726] end_request: I/O error, dev sdk, sector 1044207744
root@ms-be3003:~# dmesg |grep -c 'I/O error'
1266
"smartctl -a -d megaraid,10 /dev/sdk" confirms:
Error counter log:
Errors Corrected by Total Correction Gigabytes Total
ECC rereads/ errors algorithm processed uncorrected
fast | delayed rewrites corrected invocations [10^9 bytes] errors
read: 618183075 4 0 618183079 24 27262.666 20
write: 0 0 0 0 0 5791.725 0
verify: 3990025711 1 0 3990025712 4 2889.996 3
Non-medium error count: 7
The LD:PD mappings are 1:1, so sdk should be the 11th disk, i.e. the second disk from the end.