However - between choosing 2TB vs 3TB paintguy commented below:
'...The "server backup" in whs also backs up the OS.I'm pretty sure that whs can only back up partitions up to 2tb so if you go for a 3tb drive it will split it up. I'm going to stick to 2tb drives for that reason.'
Can you/paintguy elaborate?
This refers to a backup limitation of WHS.
WHS cannot backup any single volume bigger than 2TB. So, if you have a 3TB drive, set as a single partition, WHS cant back that up. (I believe by default, when you format a drive, WHS will split that into a 2TB and 1TB partition, unless you take steps to stop that happening).
There are ways around that limitation though. If you have a 3TB partition that has multiple folders on it, and none of them exceed 2TB in size, you can set up different backup jobs and back them up separately.
2. You mentioned a solution (below) with OS small in size- taking a image right after first install and then periodically. Sounds Good.
If I just 'start' with 250GB and 500 GB (USB external/offline) - I hope I can 'image' the entire OS as well as the data on the 250GB to the 500GB external USB drive periodically? (Do I get it right?) Or I just need to sync the data shares between internal and external periodically. Presume WHS does both?
WHS has two different backup processes.
Server backup allows you to select drives or folders on the server, including the system drive if you want, and back them up to another drive, usually an external one.
You can do a manual backup (of, say, just the system drive to allow quick restores later), and also automated, recurring backups (of whatever set of drives/folders you want - though not, each individual backup job must be less than 2TB total size).
The second backup thing of WHS is the ability to connect other computers to the server, and back them up to the server, too, on an automatic schedule. I have 3 PCs in my house that have their system drives backed up every night. This uses space very efficeintly - the backup for all 3 drives is only a bit bigger than the largest single drive among the 3.
This PC backup is for me the main reason to use WHS over one of the other systems suggested in the thread - nothing else makes PC backup so easy and efficient.