Which SAS RAID controller do you have?? This one will cover the H310 and H710 (use the 'hard drive' version, run to extract before putting on optical/USB) - found under SAS-RAID/Driver: www.dell.com/.../poweredge-r820 You can also use the embedded installation/deployment utility that can assist in installing a supported OS, which includes drivers - F10 during POST.
I created a VD to install windows server 08. The drives are attached through the front port hot swap bay, connected via SAS. It currently says that it cannot find any hard disks, I'm sure that I need the raid controller preinstall drivers for the OS to detect the drive but I cannot find it those drivers anywhere on the driver's list page on [URL]  Does anyone know where I can get the drivers? I checked the page twice and I can't find anything that even hints at preinstall drivers.
Installing Windows Server 2008 R2 on Poweredge R820, where the heck are the 
preinstall drivers?