ESX server support for now, maximum size of one datastorage up to 2TB.
But you can connect multiple datastores and create one large disk across of them (I guess?), or you can use other method's to create this large partition.
Yes this is an ESX limitation because of the older version of LVM they are using. I would assume they would finally update the kernel in ESX 4. But as posted earlier, you can connect multiple LUNs by using Extents to make them all appear as one big datastore. Also keep in mind that your individual VM's may only have the ability to create certain sizes of VMDK files, based on the block size you selected during the format of your datastore. You want to keep your block size as small as possible, but also accomodate individual disk sizes in the VMs.
As a remider:
Physical HBA Storage adapters
16 HBA’s per ESX host (dual port, quad port or 8 port)
Provides 32 paths to a single LUN
Total amount of paths supported 1024
256 LUNS can be presented to a single ESX server (128 during installation, the remainder can be added later)
256 VMFS partitions per ESX host.
VMFS Sizing
The current maximum size for a single VMFS volume is 64TB
A VMFS volume will support a maximum file size of 2TB
Maximum number of files supported 30,000
VMDK Sizing
Maximum VMDK size is currently 2TB (with 8MB block size)
Maximum VMDK size is currently 256GB (with 1MB block size)
From within a Virtual Machine
Maximum virtual HBA’s per virtual machine is 4
Maximum targets per virtual HBA 15
Maximum VMDK’s (virtual machine disks) per virtual machine 60 (windows and linux)
If you want to add another driver's you need to use manual (link I posted).