Bon alors j'ai trouvé la réponse...
il faut faire:
root# grub
GNU GRUB version 0.95 (640K lower / 3072K upper memory)
[ Minimal BASH-like line editing is supported. For the first word, TAB
lists possible command completions. Anywhere else TAB lists the possible
completions of a device/filename.]
grub> find /grub/stage1
(hd0,4)
(hd1,4)
grub> root (hd0,4)
Filesystem type is ext2fs, partition type 0xfd
grub> setup (hd0)
_________________________________________________________________
root# grub
grub> find /grub/stage1
(hd0,4)
(hd1,4)
grub> device (hd1) /dev/sdb
grub> root (hd1,4)
Filesystem type is ext2fs, partition type 0xfd
grub> setup (hd1)
Checking if "/boot/grub/stage1" exists... no
Checking if "/grub/stage1" exists... yes
Checking if "/grub/stage2" exists... yes
Checking if "/grub/e2fs_stage1_5" exists... yes
Running "embed /grub/e2fs_stage1_5 (hd0)"... 16 sectors are embedded.
succeeded
Running "install /grub/stage1 (hd0) (hd0)1+16 p (hd0,4)/grub/stage2 /grub/grub
.conf"... succeeded
Done.
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Je me suis inspiré de
http://jmrreb.dynalias.net/dotclear/index.php?2005/05/04/12-raid#htoc8
Là, lorsque je fais mes test, tout marche bien. Que j'enlève le premier disque, où le deuxième....