There are three USB ports on the Duo, one in the front and two in the back. USB drives, digital cameras, printers and UPS connections can be connected to the USB ports. I connected a 2 GB thumb drive, which was quickly recognized (Figure 12). With a USB drive plugged in, the Duo supports copy operations to and from the attached device. In addition, USB drives can be gracefully removed by selecting the Disconnect option.
Figure 12: USB drive recognized
UPS Support and Power Saving
The Duo also detects and supports UPS devices. I connected my APC UPS to a USB port on the Duo, and the make and model was accurately recognized and displayed in the status menu. Once a UPS is detected, menu choices for graceful shutdown of the Duo are available as shown in Figure 13.
Figure 13: UPS menu
Also in the Power menu, the Duo can be configured to conserve electricity and turn itself on and off on a user customizable schedule.
There are two types of backups with the Duo. The first type, which is a typical use for a NAS, is for making backups of files and data from your PC to the NAS. Netgear includes a version of NTI's Shadow (Figure 14) software for running backups on a Windows PC to the Duo.
I installed the NTI software to my XP Pro PC and configured it to run a one time backup of a folder with about 13 GB of data to the Duo, which ran without incident.
Figure 14: NTI Shadow backup
The NTI software supports not only one time and scheduled backups, but can be configured to perform continuous backups. Continuous backups have an advantage over scheduled backups, as file changes are immediately saved instead of waiting until some future scheduled backup time.
The second type of backup is to back up data on the NAS itself. Although the Duo can have dual disk drives with XRAID redundancy, making a backup of the contents of the Duo provides physical redundancy in case the Duo is stolen or destroyed.
The Duo has a built in backup utility that will allow it to run backups of its data to another network storage device. Alternatively, this same tool can be configured to run backups of data from another network storage device to the Duo.
As shown in Figure 15, Supported network files storage devices include Windows style shares, HTTP, FTP, NFS, and USB drives connected to any of the three USB ports on the Duo.
Figure 15: Built-in backup
I created a scheduled backup job to copy all my media files on the Duo to another NAS on my LAN, and a second scheduled backup job to make a copy of a different directory on another NAS on my LAN to the Duo. I scheduled both to run in the middle of the night. Unfortunately, the next day the log indicated both had failed.
Attempts to manually force the backups from the Duo Backup menu continued to fail. I tried the Connection Test feature in the Duo Backup menu that indicated the connection from the Duo to my other NAS was OK. Yet, despite multiple attempts, the backup operation always failed.
We checked into this with Netgear, apparently there is an incompatibility with the new CIFS/timestamp backup setup in the Version 4.X firmware and the way some NASes provide guest / public access. And the Connection Test function for CIFS uses a different mechanism than the backup process itself, which is why the Connection Test feature works, but the backup doesn't.
The recommended workaround, which we were able to test successfully, is to change the public share on the target NAS to a controlled-access (password protected) share. Netgear is investigating this issue further, but there is no promised / scheduled fix right now.