Some output…

drakonen@Gamont ~ $ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/md/1             1.1T   56G  989G   6% /

drakonen@Gamont ~ $ cat /proc/mdstat
Personalities : [raid1] [raid6] [raid5] [raid4]
md1 : active raid5 sdd2[3] sdc2[0] sdb2[1] sda2[2]
1171837056 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]

md0 : active raid1 sdd1[3] sdc1[0] sdb1[1] sda1[2]
96256 blocks [4/4] [UUUU]