1x128 SSD for OS, 1x8TB, 2x4TB, 2x2TB, 1x900GB. The 8TB and 1x4+1x2TB are in a hierarchical duplicated Pool, all with 2TB partitions so that WHS2011 Server Backup works. The other 4TB+2TB are in case some HDD fails. The 900GB is for trash of an further unnamed downloading client.So actually, a pretty small Server given what many users here have.