Chris is talking about VIRTUAL (or logical) disks.  The total RAID array space can be larger than 2TB (on a PERC 6 - most, but not all, controllers support VD's larger than 2TB), but 2TB is the largest individual disk size you can use.  For example, you can use 3x2TB in a RAID 5 (4TB total space), but you cannot use 2x4TB in a RAID 1 (4TB total space), since >2TB disks will not work on the PERC 6. You would need an H700 (or greater) for >2TB disks, although they are not supported on the 2950.
I have a stack of these 2950's laying around and I need to bring online around 8-10 TB of raid storage, so I thought I would just take one of these and upgrade the drives to something in the 4TB SATA range (specifically the WD Red drives -- which would give us 12TB raid 10).  I have yet to purchase anything so I'm looking for what my best options are since the PERC 6/I apparently doesn't support more than 2TB. The budget is the biggest issue.  There is room after the drives to potentially purchase an additional raid controller to replace the 6/I.  I would like something simple that doesn't require a set of cable replacements, or if it does something that's easy. looking around it appears that the H200 card is a replacement that would support these drives but requires additional components.  Anyone have any suggestions on this?  My budget is the limiting factor, if I had the resources I'd pick up a new storage server of some type, but that's not in the cards ATM.
2950 III raid options