Note that RAID-1 mirroring is only supported for two disks and you can’t mix array types. Furthermore, although the manual states that only RAID-5 arrays support hot-standby we were able to create a dual-disk mirror and assign a hot-standby drive to it. We then removed an array member whereupon the appliance used the spare drive and continued unaffected. However, if you have all four bays occupied the only way you can use all the drives is with a four-disk RAID-5 array or three-disk RAID-5 array with hot-standby. Array building is also a slow process as a four disk RAID-5 array took nearly seven hours to complete and access to the volume was denied during this phase.
The array auto-rebuild works well enough though. The default configuration is a four disk RAID-5 array and the appliance immediately acknowledged that the array was degraded when we removed one of the drives. The appliance continued to function normally in this state and when we replaced the drive it commenced an automatic rebuild. However, it did take over six hours to complete and during this time the load on the appliance’s processor rarely went below 100 per cent with a resultant drop in performance for general file sharing activities.
Only the CIFS/SMB protocols are supported and shared folders are created directly from the web interface where you can implement ACLs (access control lists) using local username and password combinations and group memberships. Good levels of control means each user and group can be denied access or allowed read only or full write access to specific shares. The appliance can also integrate with Active Directory (AD) where it becomes a domain member. This then allows you to allocate share access using the Windows domain controller’s own groups, users and policies.
At this level of the NAS market choice is becoming extensive. Buffalo’s TeraStation can’t be beaten on price while the more costly the NexonNAS 1000 provides better features including disk quotas and hardware managed RAID arrays. The SilverSTOR XS sits comfortably between these products and delivers a good range of RAID features along with hot-swap and hot-standby capabilities making it well suited to storing critical data.