How to Install OS on RAID 6 Greater Than 2TB, Help

I am trying to install the OS (server 2008 R2) on a RAID 6 configuration. I tried to install it in BIOS mode using the BIOS setup, but the D:/ data volume only sees 1.8TB. The Server has 4 2TB drives. What am I missing?

When your Server or RAID controller has a limit of 2TB per logical drive, you cannot install the OS on a RAID larger than 2TB. The cause of this problem is the partition type. The partition style may be in MBR format:

• MBR only supports hard drives up to 2TB. And you can only create up to four primary partitions on it.
• GPT suits drives with 2TB or larger capacity and support up to 128 primary partitions.

Learn more about MBR and GPT: MBR VS GPT | What's the Difference and Which Is Better

You can break the 2TB limit by changing the partition style to GPT. And then, you can use RAID 6 on Windows Server larger than 2TB.

EaseUS Partition Master Server, as a professional disk management tool, is worthy of your trust. It can help you finish the process without losing data:

Follow the steps below to change the partition style:

Note: If something is important on your drive, it's better to back it up.

Step 1. Download EaseUS Partition Master and open it.

Step 2. Next, go to the "Disk Converter" section and select "Convert MBR to GPT."

Step 3. Select the drive you want to convert and click "Convert."

Then you can view the entire drive capacity in Windows Server. For a more comprehensive step-by-step guide, please check the article: How to Convert MBR to GPT in Windows Server