The reason for the 2Tb limit under XP

When I first installed my Drobo on my Windows XP it created a 2Tb drive, and wouldn’t let me go any higher. What is the reason behind this limit?

NTFS even under XP supports 2 exabytes: and even with the default 4Kb cluster size it manages 16Tb-4Kb. Is the Drobo using 512-byte clusters? Will this change with drives using 4Kb sectors?

The limit is because XP can only recognised MBR partitions - which have a 2TB limit.

Vista and 7 can use GUID partition tables, which have a much much much higher limit

Microsoft’s GPT FAQ is also useful.