I couldn't chroot to the broken ubuntu server, may i know how can i backup and restore the mysql server without mysqldump? Could it be copy the directory and replace to the new server?
This is not guaranteed to work but you may try, and I suppose that mysql is not running.
You can copy everything from mysql data folder
/var/lib/mysql (this is the default location, check yours) and put it in the new location/server, check config to see datadir location matches, restart services and see if it works.
The configs are under
And of course not to forget the file and directory permissions.
Here are two useful links.