UnsinkableOscar,   As far as increasing the size of your SAS Virtual disk, you can see a post that discusses the process to reconfigure and expand the virtual disk here. To answer your other questions, you can indeed mix SAS and SATA drives on the same controller, but as you said you can't mix them in the same Virtual Disk. As far as the drive size, the Perc 5/i has a 2TB limitation on its Physical Disks, it can have Virtual Disks that exceed 2TB, but the Physical Disks can't exceed 2TB. I would always recommend that you keep the server up to date on BIOS, iDrac, Perc 5/i, as well as the drives.    Hope this helps.    
Hello! There is a need to expand disk space in Dell PE 2900 with the PERC 5/I controller. Now it has 3 SAS 146 GB 15K hard drives installed . Can I add SATA disk drives to this server using SAS and SATA in different arrays? What is the highest SATA disk I can install on this server? If I add 2 TB SATA hard drives (part # 341-9722 or 341-9724) do I need to update the controller firmware? Thanks!
PE 2900 SATA&SAS mix use