Actually what i want is This

I have fedora 8 installed on my pc along with working data on 30 GB HDD MAXTOR. I would like to install a new HDD of 80 GB in such a manner so it can clone my old HDD periodically basis. In case If my old HDD got corrupted the new one will automatically run without interpt my client.

Is there any software required or will I do it on command line or by script?

Thanks

Linux has lots of backup options: there are several programs for Linux (such as Amanda) or you could look at using rsync together with a cron job.

And please use better titles in future, your title should give us a brief description of your problem. In this instance, "Backup Options" would have been better.

I will tell you if you change the title of your thread to something which describes your problem )

Please explain in details

Explain what???--you're not referring to anything specific.

Looking at your original question, you are describing RAID Level 1.

As for backup utilities, a lot of distros now come with some kind of utility

http://www.crn.com/white-box/171200478

http://www.linuxfocus.org/English/Ma...ticle370.shtml

http://www.itweek.co.uk/personal-com...aster-recovery

Yep, I agree with pixellany. You're probably describing the need for a RAID 1 array. See Wikipedia for a general description of RAID.
In this case your friends are probably software RAID & eventually LVM. It might become a little bit complicated if the partition you want to "RAIDiate" is as well the root filesystem.
The links mentioned by ehawk concern as far as I understood methods of taking backups/images of an existing filesystem but they won't provide a "live" sync between HDs meaning that once that the active one fails, you'll fall back to a snapshot of the data you took in the past, losing the changes that happened between the failure and the last backup/image creation.