Some notes on the rash of 3TB external disks available. Firstly – performance differs quite a bit – if you are going to be getting drives for external backup – check the transfer speeds before parting with your cash. Secondly – remember that a 32 bit O/S is not going to recognise the 3TB approx pre formatted disk – and could cause you serious issues. If you are going to use them on 32 bit – reformat the drive and select a partition size smaller than 2TB. My experience was that it need crashed a 2003 SBS (32BIT) server doing a test backup to disk. Thirdly – if attaching to machines or more importantly servers – make sure that your bios is not set to boot from USb – and actually test the boot – saw unusual behaviour on two 2008r2 servers with different manufacturers drives attached.
Again test the boot – make sure server can start without intervention.