Can't I use any size drives I'd like (provided that it is physically compatible with the server)? Is there a reason for this? The reason I ask is because I'm currently eyeing a server that will hold 8 x 146 gb drives. Is there any reason I can't use 8 x 500 gb drives? Is this a RAID limitation? And if so, can I get around this by not using a RAID configuration (just an array of disks) or using a RAID 0 configuration?
Is it a used one? 146GB sounds like we are talking about SCSI/SCA 80-pin discs? Even if it is SAS already i wouldn't bet that SATA discs work (well), because the RAID controller was not tested with it. If you want to try SATA, go for the RAID editions that support TLER.
AFAIK there are no 2.5" SATA drives that support TLER other than perhaps the Seagate Constellations. You could always try a couple drives and see if it's an issue. Sometimes it is, some times it isn't, it depends on the controller.