I'm wondering if the Xseries 305 server supports raid arrays? If so, is there already a chip installed for it?
It does not have a RAID card builtin. It has IDE and SCSI built-in. It has this for expansion slots:
It will also only fit two slim hard drives, so you can only do RAID 0 or RAID 1 without some form of external storage, like an external SCSI array or a SAN, which would require an HBA card.
Bit of advice : your questions show a lot of "beginner" traits. That's not a bad thing, and I'm not trying to discourage you from asking questions here. However, you might do well to find a qualified or experienced person, either physically near you, or online, that you could engage in a real dialog about what you need for this project. This site is specifically for targeted questions and answers, and I think you would benefit a lot more from an "overview" type of conversation instead.