Retrieve Data From 2nd HDD After Server Failed

My server HDD got corrupted. My server provider mount a new HDD for me, and put the OLD HDD as secondary drive.

This is what they emailed me:

[root@ns1 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/hda3 149G 3.7G 138G 3% /
/dev/hda1 99M 17M 77M 19% /boot
none 498M 0 498M 0% /dev/shm
/usr/tmpDSK 485M 13M 447M 3% /tmp
/tmp 485M 13M 447M 3% /var/tmp
/dev/hdc3 149G 23G 119G 16% /backup


I have a forum data (files and database) that is still on the old HDD, I hope to retrieve it.

May I know how can I access to the data?

I tried SSH, can only go till /dev/, then don't know what to do.

What is the command in SSH that I should type in order to go to the 2nd HDD? How can I retrieve the database and files to my new HDD?