Home NAS for content sharing

Seagate Technology's Mirra Sync and Share Personal Server is a different class of product from rest of the devices I tested in a review of network-attached storage (NAS) for your home. While it backs up data from Windows and Macintosh computers, the Mirra Sync's primary purpose is to let you publish that content so that it is accessible to other users on your local network or to users over the public Internet. A classic application for the Mirra Sync would be for sharing a library of photos with family or a group of friends. It also provides a way to remotely access and update your files when you are on the road or as a way to share documents with a select group of people.

Not surprisingly, the Mirra Sync costs a bit more than the other shared-storage devices in this group. The 500GB model lists for US$599.99; a 320GB model sells for US$499.99. The unit itself is heftier than a simple shared-storage device (it measures 4½ in. wide by 8 in. tall by 8½ in. deep), and it has a relatively noisy fan that you won't want near your desktop.

Once installed, the Mirra Sync client software starts by asking you to choose the files you want to back up and can maintain up to eight revisions of each file. Backups are slowly copied directly to the Mirra Sync and are not compressed or encrypted. You can and should password protect backups because if you don't, other users on your network will be able to see and possibly delete your backups.

Once you've created your backup sets, you can choose to enable Web access for those backups and then share any folder within a backup set. Data can be shared by choosing other users on your network from a list or over the Web by entering the e-mail addresses of remote users you want to invite to access your data. Remote users then register and obtain a password at the Mirra.com Web site, which redirects them to the shared files on your Mirra Sync device. By default, users can download image files but don't have write access to shared folders. For reasons discussed below, I recommend keeping it that way.

Nuts and bolts

Mirra.com overcomes some technical challenges that you would encounter in trying to publish content directly to the Web. It maintains a link to your local Mirra Sync's IP address, and it redirects users to the resources shared on that device. That's important because your broadband modem or router assigns a dynamic IP address to the Mira Sync and other clients on your local network that is not visible from the public Internet. By using Seagate's free Domain Name System redirect service, the Mirra Sync gets around that problem -- so long as your firewall leaves UDP Port 19430 and TCP Ports 80 and 443 open. (This might explain why it would not work on my work-issued laptop).

Mirra Sync is not a traditional shared network storage device but replicates, or synchronizes, file changes between systems. That's an important difference to understand. While NAS devices use file-sharing protocols such as the Common Internet File System (CIFS) to facilitate file sharing and allow file and record locking to prevent people from overwriting changes to one anothers' files, the Mirra Sync simply uses replication to keep files up to date. When a file is changed in one location, versions in other locations are automatically overwritten with the new version.

Also, while Mirra Sync will back up My Documents and other settings, it does not back up encrypted files (such as that created by my Password Safe program), nor will it back up hidden or temporary files and folders.

You start by choosing folders and files you want backed up in the Mirra Personal Server software's Backup and Restore tab.

Once data is backed up to the Mira Sync, you enable sharing in the Web Access Tab and then share folders to users in the Sharing Tab.

Using a browser, users can log into their accounts at www.mirra.com and view shared folders and backup sets available to them on the Mira Sync server.

Once the sharing tab is selected files can be viewed on the public Internet.