You will need to install OMSA for sure to use the online raid capacity expansion option. This requires the server to be a PowerEdge server running a supported OS (Windows, VMware ESXi, SuSE or RHEL (some other linux distros may work too). Dell's raid controllers only allow for expansion if there is just a single virtual disk on the raid set (not split into 2 virtual disks). This last part impacts you as you can only use a bootdisk larger than 2TB if you change the bios to UEFI mode, which would require a full OS reinstall if you initially installed in bios mode, and you'd have to use an OS that supports UEFI, which means Windows 2008 x64 or latest, VMWare ESXi 5.x and linux support will depend on your exact distro/version.
I'm doing some experiments with configuration before setting up a production server, and I wonder if it is possible to add Physical Disks to an existing Disk Group with the intention of expanding an existing Virtual Disk onto the newly added disk. The machine has at present 4 disks, and I'm trying to plan how future expansion will work. So now I have RAID 5 setup on 3 Physical Disks with one Virtual Disk configured. There is one Unconfigured Physical Disk which does not seem to be able to be "attached" to the existing Disk Group as anything other than Hot Spare.  Is what I am trying to do possible? The idea is to have all 4 disks configured as RAID 5 and eventually as the need arises, new disks will be installed, and the one Virtual Disk will be expanded onto the new disks, and then in the OS I can then expand my partition.  The production server will have about 8 TB of data, so while of course we have backup, I don't want to deal with that unless something bad happens.  Any suggestions? Thanks.
Perc H710P add to Disk Group?