Hi, the PERC4 is a SCSI controller. The largest validated drives are 300GB. Depending on which server model it will support up to 6 drives as it is a single channel controller. 
I am about to inherit the support role for an ageing PowerEdge server running Server 2003 Standard, and equipped with a Perc 4/SC controller with two Seagate 146GB drives configured as RAID-1. One of the drives apparently failed some time ago, and the client has attempted unsuccessfully to source a replacement drive to repair the array. Due to other factors it is not feasible to replace the server with a MS Server 2012 build at this stage (though that will be the goal once the current server is stabilised). I propose in the first instance to replace both drives with new 300GB drives, and migrate all data using image backup/restore. Can anyone tell me what drives are compatible with the Perc 4/SC? Specifically, does the Perc 4/SC support SCSI and/or SAS drives (with or without suitable cable adapters, if necessary)? What is the maximum per-drive capacity?
Compatible Drives for Perc 4/SC RAID1