Currently Being ModeratedFeb 1, 2013 8:08 AM (in response to MacFergus1957)
Having your backups on the same drive as the original data won't help when that drive fails. Use an external drive.
Currently Being ModeratedFeb 1, 2013 8:09 AM (in response to MacFergus1957)
Yes, it can work.
I strongly advise against it. Your "backup" *needs* to be a physically external drive, one you can actually store at a friend's house as a saving strategy (fire, theft at your house). But that is just my opinion, not an order.
The performance impact in negligible compared the the safety factors mentioned above.
Currently Being ModeratedFeb 1, 2013 8:22 AM (in response to MacFergus1957)
It is not recommenced to use TimeMachine in a partition, either on the boot drive or externals because of problems in the past with that arrangement.
You also need hardware protection in addition to software protection.
If you want to do what I do, which is have a second 50% partition bootable clone of the first.
1: Use BootCamp software to create yourself a 50% sized partition, then exit the program. (you also can do it in Disk Utility, but it's tricky)
2: Head to Disk Utility and select the BOOTCAMP partition and change it's name and format to OS X Extended Journaled.
(To map off bad sectors in advance, use Disk Utility Erase with the next to last on the right selection, improves reliability and makes for faster reads)
3: Download Carbon Copy Cloner, now select your Macintosh HD partition and clone it to the second partition.
4: Whenever you want to boot from the second partition, just hold the option key down on the keyboard to select it to boot from.
You can access the folders on the second boot partition as well, to grab deleted files you accidentally erased (which is a rare thing for most to occur) however you should leave it alone and as a clone.
You can update the clone when you need to, or schedule it to run automatically.
You should also do this occasionally with a external drive, as the internal drive can die and take both partitions with it.
I currently do this with my laptop, that way if I'm mobile and have a serious issue, I can boot from the cloned partition in seconds without carrying a drive around. If I need large space for something I wasn't aware of, I can erase the clone partition and later clone it again.
Software does all the work, just pick a time your not using the machine and let it work. Painless really.