MBR / GPT partition style and Windows Server 2008 R2 system partition

GPT partition style has been introduced to expand the limitations of the MBR (2TB).

Today with disks of 2TB, you can have a raid system much larger than 2TB (eg : on a NAS, file server…)

If you wish to install a system on a 8TB partition for instance you need to create a partition on a GPT partition style of 8TB.

Windows can handle disks larger than 2TB, but not for the windows system installation…
Even Windows Server 2008R2 can only install on a MBR partition style, so up to a 2TB partition.

So you will have to split your raid into 2 and have Windows installed on the first and have data on the second.

For instance :

We have 5x 2TB HDD (initially a 8GB raid 5)

It can become :

2x 2TB HDD (raid 1) for Windows

3x 2TB HDD (raid 5) for data

So there is a lot of spare space on the first partition (system). Of course you can split into 2 partitions (system + data).

So you’d better have 2 small disks in raid 1 for the system and then have multiple large disks for data.

Be aware that NAS servers are usually sold with a bunch of large disks.