I need to establish a data backup strategy using 1 local back up server and 1 remote server that will be a mirror of the local server. Data sources from which data needs backed up include PCs, Macs, and Windows 7 and Linux servers. The local backup server will house 1 - 3 TB SAS SSDs, the remote server will likely have HDDs. Total current data to backup = 15TB, with 36-40TB estimated in 3-5 years.
Please recommend what RAID configuration I should employ for both backup servers.