This document summarizes Marek Lubinski's presentation on implementing NexentaStor as the backend storage for LeaseWeb's Express Cloud platform. Initially, storage performance issues arose using Linux NFS on Supermicro servers. NexentaStor was selected for its ZFS capabilities. The initial design underestimated I/O sizes and overestimated cache hit ratios, resulting in performance problems during VM migration. Through sizing changes, such as adding RAM, SSD caching, and mirrored vdevs, a final configuration was achieved that met performance needs. Lessons included using mirrored vdevs for high demand, achieving high cache hit ratios, and testing configurations first.