C’est bon il fallait tout simplement faire “q”
L’installation c’est passée sans soucis, au reboot j’avais bien le nouveau noyau proposé par GRUB
Et la juste après le check des disques durs RAID…paf ecran bloqué avec un joli nuage de point et rien de plus à l’affichage 
Pas de ping, donc impossibilité de se connecter dessus en ssh.
Pas d’autres solutions que de rebooter à la sauvage et de choisir l’ancien noyau, la il est en train de checker md2.
Pour retirer ce noyau qui ne va pas:
apt-get remove -t squeeze-backports linux-image-2.6-amd64 ??
ou
apt-get remove -t squeeze-backports linux-image-2.6-amd64 --purge ??
si ça peut aider, voila ce que j’ai recupéré dans syslog au moment du boot du nouveau noyau qui plante
Sep 19 19:26:18 minusserveur dkms_autoinstaller: vboxhost (4.1.2): Installing module on kernel 2.6.39-bpo.2-amd64.
Sep 19 19:26:18 minusserveur dkms_autoinstaller: Kernel headers for 2.6.39-bpo.2-amd64 are not installed. Cannot install this module.
Sep 19 19:26:18 minusserveur dkms_autoinstaller: Try installing linux-headers-2.6.39-bpo.2-amd64 or equivalent.
Sep 19 19:26:18 minusserveur dkms_autoinstaller: virtualbox-ose (3.2.10): Installing module on kernel 2.6.39-bpo.2-amd64.
Sep 19 19:26:18 minusserveur dkms_autoinstaller: Kernel headers for 2.6.39-bpo.2-amd64 are not installed. Cannot install this module.Sep 19 19:26:18 minusserveur dkms_autoinstaller: Try installing linux-headers-2.6.39-bpo.2-amd64 or equivalent.
Sep 19 19:26:44 minusserveur kernel: [ 5663.904876] SGI XFS with ACLs, security attributes, realtime, large block/inode numbers, no debug enabled
Sep 19 19:26:44 minusserveur kernel: [ 5663.907265] SGI XFS Quota Management subsystemSep 19 19:26:44 minusserveur kernel: [ 5663.937115] JFS: nTxBlock = 8192, nTxLock = 65536
Sep 19 19:26:45 minusserveur kernel: [ 5663.980474] NTFS driver 2.1.29 [Flags: R/W MODULE].
Sep 19 19:26:45 minusserveur kernel: [ 5664.027358] QNX4 filesystem 0.2.3 registered.Sep 19 19:26:45 minusserveur kernel: [ 5664.090894] Btrfs loaded
Sep 19 19:26:45 minusserveur os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sda1
Sep 19 19:26:45 minusserveur 50mounted-tests: debug: /dev/sda1 type not recognised; skippingSep 19 19:26:45 minusserveur os-prober: debug: os detected by /usr/lib/os-probes/50mounted-tests
Sep 19 19:26:45 minusserveur os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sda2Sep 19 19:26:45 minusserveur os-prober: debug: /dev/sda3: is active swap
Sep 19 19:26:45 minusserveur os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sda4
Sep 19 19:26:45 minusserveur os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sda5
Sep 19 19:26:45 minusserveur os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sdb1
Sep 19 19:26:45 minusserveur kernel: [ 5664.507490] FAT: utf8 is not a recommended IO charset for FAT filesystems, filesystem will be case sensitive!
Sep 19 19:26:45 minusserveur kernel: [ 5664.515512] FAT: Filesystem error (dev sdb1)
Sep 19 19:26:45 minusserveur kernel: [ 5664.515520] fat_get_cluster: invalid cluster chain (i_pos 0)Sep 19 19:26:45 minusserveur os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sdb2
Sep 19 19:26:45 minusserveur os-prober: debug: /dev/sdb3: is active swap
Sep 19 19:26:45 minusserveur os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sdb4
Sep 19 19:26:45 minusserveur os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sdb5
Sep 19 19:26:45 minusserveur os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sdc1
Sep 19 19:26:45 minusserveur kernel: [ 5664.652271] FAT: utf8 is not a recommended IO charset for FAT filesystems, filesystem will be case sensitive!Sep 19 19:26:45 minusserveur kernel: [ 5664.653235] FAT: Filesystem error (dev sdc1)
Sep 19 19:26:45 minusserveur kernel: [ 5664.653243] fat_get_cluster: invalid cluster chain (i_pos 0)
Sep 19 19:26:45 minusserveur os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sdc2Sep 19 19:26:45 minusserveur os-prober: debug: /dev/sdc3: is active swap
Sep 19 19:26:45 minusserveur os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sdc4
Sep 19 19:26:45 minusserveur os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sdc5Sep 19 19:27:08 minusserveur AptDaemon: INFO: Initializing daemon
Sep 19 19:27:16 minusserveur shutdown[21597]: shutting down for system reboot
Sep 19 19:27:16 minusserveur init: Switching to runlevel: 6Sep 19 19:27:17 minusserveur avahi-daemon[1783]: Withdrawing workstation service for pan0.
Sep 19 19:27:17 minusserveur apcupsd[1580]: apcupsd exiting, signal 15
Sep 19 19:27:17 minusserveur apcupsd[1580]: apcupsd shutdown succeeded
Sep 19 19:27:17 minusserveur authdaemond: stopping authdaemond childrenSep 19 19:27:17 minusserveur bluetoothd[1769]: bridge pan0 removed
Sep 19 19:27:17 minusserveur bluetoothd[1769]: Stopping SDP server
Sep 19 19:27:17 minusserveur bluetoothd[1769]: Exit
Sep 19 19:27:18 minusserveur kernel: [ 5697.373762] md: md2 still in use.
Sep 19 19:27:18 minusserveur kernel: [ 5697.373845] md: md1 still in use.Sep 19 19:27:18 minusserveur kernel: [ 5697.373930] md: md0 still in use.
Sep 19 19:27:18 minusserveur kernel: [ 5697.374140] md: md2 still in use.
Sep 19 19:27:18 minusserveur kernel: [ 5697.374299] md: md1 still in use.
Sep 19 19:27:18 minusserveur kernel: [ 5697.374402] md: md0 still in use.
Sep 19 19:27:18 minusserveur postfix/master[2188]: terminating on signal 15
Sep 19 19:27:18 minusserveur mysqld: 110919 19:27:18 [Note] /usr/sbin/mysqld: Normal shutdown
Sep 19 19:27:18 minusserveur mysqld:
Sep 19 19:27:18 minusserveur mysqld: 110919 19:27:18 [Note] Event Scheduler: Purging the queue. 0 events
Sep 19 19:27:18 minusserveur mysqld: 110919 19:27:18 InnoDB: Starting shutdown...
Sep 19 19:27:18 minusserveur kernel: [ 5697.705312] mtrr: no MTRR for c0000000,1000000 found
Sep 19 19:27:18 minusserveur snmpd[2373]: Received TERM or STOP signal... shutting down...
Sep 19 19:27:18 minusserveur avahi-daemon[1783]: Got SIGTERM, quitting.
Sep 19 19:27:18 minusserveur avahi-daemon[1783]: Leaving mDNS multicast group on interface eth0.IPv6 with address fe80::f66d:4ff:fed8:3900.
Sep 19 19:27:18 minusserveur avahi-daemon[1783]: Leaving mDNS multicast group on interface eth0.IPv4 with address 192.168.1.10.
Sep 19 19:27:18 minusserveur avahi-daemon[1783]: avahi-daemon 0.6.27 exiting.
Sep 19 19:27:19 minusserveur named[1592]: received control channel command 'stop -p'
Sep 19 19:27:19 minusserveur named[1592]: shutting down: flushing changes
Sep 19 19:27:19 minusserveur named[1592]: stopping command channel on 127.0.0.1#953
Sep 19 19:27:19 minusserveur named[1592]: stopping command channel on ::1#953
Sep 19 19:27:19 minusserveur named[1592]: no longer listening on ::#53
Sep 19 19:27:19 minusserveur named[1592]: no longer listening on 127.0.0.1#53
Sep 19 19:27:19 minusserveur named[1592]: no longer listening on 192.168.1.10#53
Sep 19 19:27:19 minusserveur named[1592]: exiting
Sep 19 19:27:19 minusserveur kernel: [ 5698.733501] fuse exit
Sep 19 19:27:23 minusserveur mysqld: 110919 19:27:23 InnoDB: Shutdown completed; log sequence number 0 280939
Sep 19 19:27:23 minusserveur mysqld: 110919 19:27:23 [Note] /usr/sbin/mysqld: Shutdown complete
Sep 19 19:27:23 minusserveur mysqld:
Sep 19 19:27:23 minusserveur mysqld_safe: mysqld from pid file /var/run/mysqld/mysqld.pid ended
Sep 19 19:27:24 minusserveur acpid: exiting
Sep 19 19:27:24 minusserveur AptDaemon: INFO: Shutdown was requested
Sep 19 19:27:24 minusserveur rpc.statd[1307]: Caught signal 15, un-registering and exiting
Sep 19 19:27:25 minusserveur kernel: Kernel logging (proc) stopped.
Sep 19 19:27:25 minusserveur rsyslogd: [origin software="rsyslogd" swVersion="4.6.4" x-pid="1484" x-info="http://www.rsyslog.com"] exiting on signal 15.