Merci Jean-Michel pour ta réponse. Le problème est que mon fichier /var/log/dmesg date de décembre 2014, date du dernier reboot réussi du serveur.
Donc à priori, je pense que le serveur ne démarre pas du tout, à moins qu'il ne log rien au démarrage...
J'ai beau retourner ma config dans tous les sens, je ne vois pas où peut se trouver le problème.
J'ai 2 disques en RAID logiciel, avec /dev/md1 pour le système / et /dev/md3 avec LVM pour les datas...
~# fdisk -l
Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
[...]
Device Boot Start End Blocks Id System
/dev/sda1 * 4096 20482048 10238976+ fd Linux raid autodetect
/dev/sda2 20482049 40960000 10238976 82 Linux swap / Solaris
Partition 2 does not start on physical sector boundary.
/dev/sda3 40960001 1953517568 956278784 fd Linux raid autodetect
Partition 3 does not start on physical sector boundary.
Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
[...]
Device Boot Start End Blocks Id System
/dev/sdb1 4096 20482048 10238976+ fd Linux raid autodetect
/dev/sdb2 20482049 40960000 10238976 82 Linux swap / Solaris
Partition 2 does not start on physical sector boundary.
/dev/sdb3 40960001 1953517568 956278784 fd Linux raid autodetect
Partition 3 does not start on physical sector boundary.
Disk /dev/md3: 979.2 GB, 979229409280 bytes
2 heads, 4 sectors/track, 239069680 cylinders, total 1912557440 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Alignment offset: 3584 bytes
Disk identifier: 0x00000000
Disk /dev/md3 doesn't contain a valid partition table
Disk /dev/md1: 10.5 GB, 10484645888 bytes
2 heads, 4 sectors/track, 2559728 cylinders, total 20477824 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000
Disk /dev/md1 doesn't contain a valid partition table
Disk /dev/mapper/vg--vm-lv--vm: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders, total 209715200 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/vg--vm-lv--vm doesn't contain a valid partition table
Disk /dev/mapper/vg--vm-lv--bck: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders, total 62914560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/vg--vm-lv--bck doesn't contain a valid partition table
Disk /dev/mapper/vg--vm-lv--data: 805.3 GB, 805306368000 bytes
255 heads, 63 sectors/track, 97906 cylinders, total 1572864000 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00000000
Disk /dev/mapper/vg--vm-lv--data doesn't contain a valid partition table
Je me pose une question bête : GRUB doit bien être installé sur /dev/sda, et pas sur /dev/md1 ??