Backup, rebuild and re-partition rackspace unmanaged server and unmanaged server and troubleshoot database

Skillsets required:
- Linux server administration
- Codeigniter development

We are getting DB problems, here is the new job spec:

1. backup rebuild/repartition server.(or move to newly created partition). We have 320 gig HD but only 9gig partition for system.

Disk /dev/xvda: 326.4 GB, 326417514496 bytes
Disk identifier: 0x7d03bd73
Disk /dev/xvdc: 17.2 GB, 17179869184 bytes
Disk identifier: 0x00000000


/dev/xvda1 9.4G 7.9G 1020M 89% /
none 3.9G 120K 3.9G 1% /dev
none 3.9G 0 3.9G 0% /dev/shm
none 3.9G 100K 3.9G 1% /var/run
none 3.9G 0 3.9G 0% /var/lock

2. Update the server software (currently: Ubuntu 11.04 (Natty Narwhal) )

(The above would need to be performed outside of office hours to minimise downtime (9-5:30))

3. troubleshoot database issue. Have had mysql stop few times this morning. (This started when the HD ran out of space, but there is some space now but it keeps freezing).
I've ran mysqlcheck and repaired but it keeps falling over. Couple of tables in particular seem to need repairing each time.
Though this may be the php running a very large sql statement (hence the codeigniter skills required incase this is the issue). not sure.