I have an HP Proliant DL360 G6 server running Windows Server 2003. It is our domain controller. I currently have two 146 GB drives mirrored in the system. We have about 10% of free space left currently. I purchased a third 146 GB drive and installed in the third port. The Array software is telling me that I cannot expand since it is not the equal number of drives, but I can convert to Raid 5. My question is, should I purchase another drive to expand, or convert to Raid 5? If I do convert to Raid 5, should I go ahead and purchase another drive as a hot spare? Once I convert to Raid 5, how do I expand the storage on the logical drive? Do I do this in the array software, or do I do this through the OS? Any help is appreciated, and I will give any additional info needed. Thanks in advance.