Advice on RAID Setup

Howdy,

So rebuilding a network and having to use existing hardware due to budget limitations, until we can replace hardware next year.

The server itself is an old Dell PowerEdge R900 - specced out with multiple CPU's and ~64GB of RAM. It has the PERC 6 / i RAID controller with 5 x 2TB hard disks.

My initial plan was 1 x RAID 10 Array with a hotspare. This worked and Windows loaded, however due to its age and non UEFI BIOS, it can't see anything more than 2TB. So i went back to the beginning and tried to create 2 partitions within the Windows server setup screen - but again it will create one partition and then throws errors trying to create additional partitions on the 1.6TB of remaining hard disk (doesn't matter what size).

From reading online it appears you can't create multiple virtual drives on a single RAID 10 array like i've done in the past with HP servers.

This leaves me with two options that i can think of..

1) Create 2 x RAID 1 mirrors and use 1 drive as a hot spare. This will give me 2 x ~2TB drives

2) Create 1 x RAID 1 mirror and 1 x RAID 5 with no hot spares (I actually have a physical spare drive so the hotspare isn't critical). This will give me maximum storage.

The server will run 1 x 2016 Domain controller for about 20 users, 1 x 2008 RDS server for 3 - 4 users, and i was planning to run 1 x application/file server too.

Open to suggestions and ideas.