comme ça :
mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/cciss/c0d1p1 /dev/cciss/c0d1p2

j'ai cru qu'il avait perdu la config mais quand je refais la commande il me sort ça :

mdadm: /dev/cciss/c0d1p1 appears to contain an ext2fs file system
size=104420K mtime=Thu Jan 18 16:24:56 2007
mdadm: /dev/cciss/c0d1p1 appears to be part of a raid array:
level=1 devices=2 ctime=Thu Jan 18 15:51:03 2007
mdadm: /dev/cciss/c0d1p2 appears to contain an ext2fs file system
size=104420K mtime=Thu Jan 18 16:25:02 2007
mdadm: /dev/cciss/c0d1p2 appears to be part of a raid array:
level=1 devices=2 ctime=Thu Jan 18 15:51:03 2007
Continue creating array? n
mdadm: create aborted.