NAS1 is used for Active Directory files sharing, ESX 5.1 server (iscsi), streaming video, etc .... and NAS2 is only used for backup using rsync beetween nas1 et nas2 everyday. i have to say this product is very reliable as you can see !
Though you must be running downrev firmware, as there have been updates over the past ~two years. Some of them addressed security concerns, so you might consider an update (even though it means a reboot).
