"Our server has an array of 3 RAID 5, 70GB drives in rack 0. This gives us a139GB logical drive and one hot swap." All the disks are hot-swap, meaning they can be removed/inserted while the system is running.  RAID 5 uses one disk's worth of disk space for parity (not one particular disk, but one disk's worth of space) ... the data and parity are striped equally across the RAID 5 disks, meaning any one disk can fail and maintain the accessibility of the server/data, and no one disk is more important than the others. "i had to search for OpenManage Server Administrator to get the right version" Because your firmware is out of date.  What version did you end up installing? Not sure what you mean by "rack", but to add two more 73GB disks to your RAID 5, you insert the disks, then in OMSA, go to Storage, PERC, Virtual Disks, then select Reconfigure from the dropdown menu of Available Tasks for the RAID 5, select the two new disks, then RAID 5 as the target RAID level.  It will take several hours to complete.
We have a Poweredge server with 3-70GB Cheetah drives. Last week an amber LED started flashing and one of the drives failed. the logical drive shows 139GB,(which makes sense since there were only 2 drives working).  we received the new drive today and plugged it in. and ut theused the PERC utility to mount the new drive.  Everything appeared fine except the logical drive is still saying 139GB instead of 210GB and the amber LED is still flashing.  what are we missing?
PowerEdge 2600 SCSI Drive