Maximum supported disk partition sizes?

Hi folks,

I have an iSCSI LUN that i'm trying to partition for use in a Xen VM.
fdisk -l says that the LUN is 3011.9 GB, 3011946479616 bytes in size.
When i try to create partitions on it, however, the maximum size i can
create is 2166.0 GB, 2166004076544 bytes.

Is there some sort of hard limit on the size of partitions that can be
created?

Thanks in advance,
Paul