why is xserve raid limited to 1tb drives can i fit larger drives

There is no way around it - at least not officially.

The firmware in the XServe RAID - that is, the actual code that deals with interacting/reading/writing to the drives - was specifically tuned to the drives that shipped in the XServe RAID - namely 250GB, 400GB, 500GB and, ultimately, 1TB, which was the largest drive in common use when the XServe RAID was discontinued. As such, the device doesn't know how to talk to larger drives.

That said,you could try putting in a larger drive and seeing if it works, but I wouldn't hold out much hope. I certainly would not run the RAID with different sized drives (or even drives from different vendors).

At the end of the day, if you want more space, look for other options, or find another XServe RAID and chain them together.

If i was to put say 4tb drives in the raid and then partition them it into 1tb partitions do you think that would work?

No. I'm absolutely sure it would not.

The problem is far more low-level than that - think of it more as the RAID controller having no idea how to talk to a 4TB drive - it expects 1TB drives at most.

Additionally, the RAID controller expects to talk to the drive directly, and doesn't understand partitions (partitions are just logical, not physical constraints). Assuming you could partition the drive (which you can't, because the UI doesn't support it), the two outcomes would be 1) the RAID ignores the partition map, or b) it uses the first partition it finds. Hard to say which is more likely since you don't have an option to partition the drives anyway 🙂

But even if I am wrong (it does happen occasionally 😉 ) and it recognizes the partitions, the RAID controller still only expects 14 drives (partitions), and isn't likely to build an array over 56 partitions.

I know this might seem a stupid question but is there any way to increase the size of drives the raid controller will talk recognize?

Well, yes - that's what the firmware does. each time the XServe RAID has supported larger drives there has been a corresponding firmware update to include that support. The issue is that the firmware code is proprietary and owned by Apple, so no one else (least of all you or me) can make the necessary changes. Apple could do it but the chances of that are... well, let's just say it's not high 🙂

You are limited only ny the number of fiber channel ports. If you have a quad-port card you can connect two XServe RAIDs. If you have a fiber channel switch you can connect any number (up to the number of ports on the switch)