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grub upgraded on Ubuntu 14.04.2 LTS which device should be used for install?


GwynethLlewelyn
16/05/2015, 15h35
Hi,

This is a simple question, I think. I just want to make sure I'm not doing anything wrong.

I'm using Ubuntu 14.04.2 LTS (now on a custom kernel, not OVH/Kimsufi's). A recebt upgrade has updated grub and it asks me now where it should be installed!

I'm given the following options:

[ ] /dev/sda (1000204 MB; Hitachi_HUA722010CLA330)
[ ] /dev/sdb (1000204 MB; Hitachi_HUA722010CLA330)
[ ] /dev/md2 (997843 MB; ???)
[ ] /dev/md1 (208 MB; ???)


And here is what those filesystems are pointing to:


$ df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/md2 959034776 905267100 5028456 100% /
udev 1991188 4 1991184 1% /dev
tmpfs 400440 536 399904 1% /run
none 4 0 4 0% /sys/fs/cgroup
none 5120 0 5120 0% /run/lock
none 2002188 0 2002188 0% /run/shm
none 102400 0 102400 0% /run/user
/dev/md1 193178 47151 131768 27% /boot

$ sudo mount
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
udev on /dev type devtmpfs (rw,relatime,size=1991188k,nr_inodes=497797,mode=7 55)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode =000)
tmpfs on /run type tmpfs (rw,nosuid,noexec,relatime,size=400440k,mode=755)
/dev/md2 on / type ext4 (rw,relatime,errors=remount-ro,data=ordered,jqfmt=vfsv0,usrjquota=quota.user,g rpjquota=quota.group)
none on /sys/fs/cgroup type tmpfs (rw,relatime,size=4k,mode=755)
none on /sys/fs/fuse/connections type fusectl (rw,relatime)
none on /sys/kernel/debug type debugfs (rw,relatime)
none on /sys/kernel/security type securityfs (rw,relatime)
none on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k)
none on /run/shm type tmpfs (rw,nosuid,nodev,relatime)
none on /run/user type tmpfs (rw,nosuid,nodev,noexec,relatime,size=102400k,mode =755)
none on /sys/fs/pstore type pstore (rw,relatime)
/dev/md2 on /var/www/clients/client7/web27/log type ext4 (rw,relatime,errors=remount-ro,data=ordered,jqfmt=vfsv0,usrjquota=quota.user,g rpjquota=quota.group)
/dev/md2 on /var/www/clients/client9/web29/log type ext4 (rw,relatime,errors=remount-ro,data=ordered,jqfmt=vfsv0,usrjquota=quota.user,g rpjquota=quota.group)
/dev/md2 on /var/www/clients/client11/web31/log type ext4 (rw,relatime,errors=remount-ro,data=ordered,jqfmt=vfsv0,usrjquota=quota.user,g rpjquota=quota.group)
/dev/md2 on /var/www/clients/client3/web33/log type ext4 (rw,relatime,errors=remount-ro,data=ordered,jqfmt=vfsv0,usrjquota=quota.user,g rpjquota=quota.group)
/dev/md2 on /var/www/clients/client1/web35/log type ext4 (rw,relatime,errors=remount-ro,data=ordered,jqfmt=vfsv0,usrjquota=quota.user,g rpjquota=quota.group)
/dev/md2 on /var/www/clients/client3/web37/log type ext4 (rw,relatime,errors=remount-ro,data=ordered,jqfmt=vfsv0,usrjquota=quota.user,g rpjquota=quota.group)
/dev/md2 on /var/www/clients/client13/web39/log type ext4 (rw,relatime,errors=remount-ro,data=ordered,jqfmt=vfsv0,usrjquota=quota.user,g rpjquota=quota.group)
/dev/md2 on /var/www/clients/client13/web43/log type ext4 (rw,relatime,errors=remount-ro,data=ordered,jqfmt=vfsv0,usrjquota=quota.user,g rpjquota=quota.group)
/dev/md2 on /var/www/clients/client6/web61/log type ext4 (rw,relatime,errors=remount-ro,data=ordered,jqfmt=vfsv0,usrjquota=quota.user,g rpjquota=quota.group)
/dev/md1 on /boot type ext4 (rw,relatime,errors=remount-ro,data=ordered)
systemd on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,name=systemd)


Now I understand that /dev/sda and /dev/sdb are the physical disks, on top of which RAID1 is implemented via fakeraid. /dev/md1 is the small boot partition, /dev/md2 is where 'everything else' (including the root partition) is stored.

This thread on askubuntu.com shows how it is important to pick the right one: http://askubuntu.com/questions/43036...m-installation

I've tried to install it to /dev/md1 first (it's supposed to be the boot partition) and then to /dev/md2 (the root partition). In both cases, grub fails to install. Then I tried to install it on (both) /dev/sda and /dev/sdb, which are supposed to be the physical disks. This seems to have worked, but I'm now scared to reboot the server.

How can I make sure that grub is properly installed/upgraded and have no fear of rebooting?