In an upcoming project, I will need to deploy a large scale storage network - we're projecting between 2 ~ 5 TB after one year, but in any case it should be scalable. Since i'm an apple user myself, I have been looking into the Apple offerings and find them (the XServe RAID anyway) quite reasonable compared to some of the SAN offerings by IBM, HP etc... I have several questions about Apple hosting though.

1) Would I encounter any compatibility problems? I presume that PHP/Apache/MySQL is all working already, but as the system expands and we may venture into other hosting software, would I find compatibility problems with a 64-bit G5?

2) I'm a bit confused by apple's product offerings. My plan was originally to buy:
i. An Apple XServe
ii. An XServe RAID

- are these two sufficient on its own? I gather the XServe RAID is already a separate unit, connecting to the XServe via fibre channel. How then does the Apple SAN help me further? And if the SAN is just a piece of software (?), do I then buy another XServe on top of the SAN just to run the SAN? Apple's website makes it all look very reasonable in terms of pricing... but it's not clear on if there are any hidden costs, or if we end up having to buy more things just to get it to work.

Any help would be gratefully appreciated.