How to reset root password in ubuntu server

We seem to have misplaced the root password for a dedicated server we have (with OVH).
I asked them for instructions on how to reset the root password and this is what they said:

1. Reboot in rescue mode
2. login via ssh (using info provided in an email)
3. mount the disk with 'mount /dev/sda1 /mnt/'
4. execute 'chroot /mnt/'
5. change the password with 'passwd root'
6. reboot (in normal mode)

i followed the instructions but when i got to step 3 i get this error

mount: unknown filesystem type 'linux_raid_member'

this is the outcome of fdisk -l

    Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0009307f

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048    20973568    10485760+  fd  Linux raid autodetect
/dev/sda2        20973569  1952468992   965747712   fd  Linux raid autodetect
/dev/sda3      1952468993  1953520064      525536   82  Linux swap / Solaris

Disk /dev/md2: 988.9 GB, 988925591552 bytes
2 heads, 4 sectors/track, 241436912 cylinders, total 1931495296 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/md2 doesn't contain a valid partition table

Disk /dev/md1: 10.7 GB, 10737352704 bytes
2 heads, 4 sectors/track, 2621424 cylinders, total 20971392 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/md1 doesn't contain a valid partition table

i tried

mount /dev/md1 /mnt

and continued with instructions 4-6 but the password was not reset (it looks like it was only done for the rescue disk)

how can i change the password? (i asked the hosting company but they are taking their sweet time to reply)

thanks