I was going to say the same; use smartctl to find out what is logged in the drives logs too: 'smartctl -x /dev/sda' 'smartctl -x /dev/sdb' (I think -x is the right switch). I would start by unmounting the /dev/mdN drives but not dismantling the arrays, and then query all that you can query with mdadm. I would say there is are a lot of log entries in dmesg and syslog/messages. Start from there. No more reboots. They only thing you get from crashes and reboots is further corruption at the _filesystem_ lavel (not hardware or RAID). If you find that a particular drive is failing, take it out of the raid pool with something like: 'mdadm /dev/mdN --fail /dev/sd[a][b]N' or 'mdadm /dev/mdN --remove /dev/sd[a][b]N' whichever applies depending on what you want to do (declare it failed or just remove it). Filesystems should be unmounted cleanly, or just mounted read-only ahead of time, if you want to continue gettigndiagnostics by launching programs. You can force those filesystems to be mounted ro at boot-time in case you get more of those crashes. The logs are your friend. IN