Hi there,

I am looking for a linux program that will allow me to back up my hard drive to an exact other hard drive. I have a 320 GB SATA in my Desktop computer as a backup drive and a 320 SATA usb external that I use as my main hard drive. I want to be able to make changes on the external such as creating new directories, modifying existing files, downloading new files, deleting old files, renaming existing directories and changing their contents etc. I then want to be able to have all those changes appear exactly on my back up drive in the desktop machine, without having to delete its entire contents and transfer over a new 320 GBs of data. Is there a program that can help me out ?

I know RAID does this, but Id rather not use it because sometimes I take the external on trips. I want to be able to come home from my trip and mirror the hard drive I used while away. This means the drives will not always be together.

Thanks
Christopher

dd if=/dev/sda of=/dev/sdb

should do the trick, assuming that's the right names for the two drives.

in reality i'd say that raid WOULD be a better solution, there's no problem whatsoever in running a raid1 mirror on one drive for as long as you want, and just plug it back in again to update the pair once you add it to the machine you originally took it out of.

The way I understood the OP's question, he wants to keep any changes he made on the portable drive when he is away. Does Raid 1 resync by honoring the most recently dated changes when it merges the contents?

I think that unison should do what you want. unlike rsync it can handle changes to both drives and merge them in a smart manner, giving you the opportunity to review the changes. When dealing with certain files (text based) that have been changed on both drives it can merge the differences. I use it to keep my usb stick and a copy of the files on it in sync and it works quite well.

I don't think dd is an option here.. it transfers bits and bytes from the drive (and therefore the filesystem structure). It would also require transfering a full 320GB each time.