Situacia:
povodny RAID1 [md1] sa skladal z [hdc2] a [hdd2].
potrebujem ho zmenit na RAID5 zo 4 diskov [hda-d]2

tymto som z [md1] vybral disk [hdc2]:

raidsetfaultly /dev/md1 /dec/hdc2
raidhotremove /dev/md1/dev/hdc2

md1 : active raid1 hdd2[1]
107426560 blocks [2/1] [_U]

vytvorime novy RAID5 device bez jedneho disku [hdd2]
mdadm --create /dev/md5 --level=5 --raid-devices=4 /dev/hd[abc]2 missing

md5 : active raid5 hdc2[2] hdb2[1] hda2[0]
322279680 blocks level 5, 64k chunk, algorithm 2 [4/3] [UUU_]

potom uz len vytvorit fs, namountovat oba raidy, prekopirovat data
raidstop md1
raidhotadd /dev/md5 /dev/hdd2
a uz len pockat kym sa to syncne a vymazat md1 z raidtabu..