Datastore not formatting larger than 2TB

Hi,

I have a server with ESXi5.1 and a LSI non raid card which connects to a Infortrend RAID DAS. The server and ESXi are seeing the raid and reporting correctly at 3TB. However when I go to 'Add Storage...', and choosing VMFS-5 of course, the formatting page says:

Disk layout: Format: GPT Primary Partitions Capacity 2.72TB

File system:Maximum filesize 2TB

What does it mean by Maximum filesize 2TB ???

Also in the VMware EXSi 5.1 maximum capacities, it states it can only have a 106k files ??? What is this in relations too ??

I'm making a VM file server which I want to use the DAS for the full storage. Is it better to use VMDK or RDM ??

Thanks

Ed