Partitioning an External HDD for efficient backup

My son (college) will be using a WD 500 GB external to backup his Sager 2090 (hope it gets here soon). I am going to use Norton Ghost 12 to do a full image backup and a periodic backup for restores in case he drops it or the drive dies. The Sager will have a 160GB HDD.
I am creating two NTFS partitions on the external, one for the backup and one for music and video files (IPOD stuff basically).

Does the backup partiton need to be right at 160GB or does it need to be slightly larger ( how much larger)? My thought is that there may need to be some buffer space as the drives fragment the backup may take more than the sum total of the restore GB. But I want to make the backup partiton as small as possible to leave as much usable GB for the other partion.

Am I making any sense? Am I overthinking this? I have never done a full restore setup like this before, I have just saved a backup of irreplacable photos and such.:confused2:

 

A Ghost image is typically a compressed (with extensions like GHO/GHS) file that can sit anywhere on the filesystem (Ghost supports many filesystems, so ntfs is well covered). So, you don't really need to partition the external disk if you don't want to. Just create one folder for Ghost Images, and save your ghost image files there.

If you want to create a separate partition (for safety e.g. if one partition goes to dumps, the other is still accessible) for ghost images, you can safely create a partition of 150GB (or even less but I would recommend 150GB). Most of the time you won't even use that much for the Ghost Images because the heavy compression will compress it down a lot. My typical vista install with tonnes of biggies loaded, for about a 15GB used space, compressed nicely to about 6GB.

Advantage of one 500GB partition is that all the space is available to Ghost as well as any other program that wants.

 

Hmmm... so you recommend I don't partiton at all since, if I understand, the backup just becomes a file on the external?

 

that's exactly right. Reserving space and creating separate multiple partitions for different kind of data has its advantages but if its just mainly a backup drive, I wouldn't worry about partitioning it.

Since this partition is going to be mostly backups and songs etc., which are huge files, make sure you choose large enough block size for the fastest performance while formatting. Something like 64k.

 

Yea, devsk is correct. I have used Norton Ghost to backup my 80gb full out of 200gb hard drive in my notebook onto a home server. Before you begin the backup you are asked how much compression you want to do on your backup. I chose normal compression and my 80gb data was compressed to about 60gb. It also warns you that more compression may cause data loss but that does not occurr as often as you may think.