Replication risks

Replication is a two-way street and can quickly get confusing if you are allowing others to update or add to your backup set. Let's say you back up a folder and share it with Joe. It's possible for another user to download and synchronize a local copy of your shared folder. That means that changes the user makes to the files in their local copy of your shared folder are then replicated back up to the Mirra Sync server and then down to the original source copy on your desktop, overwriting it. If you both have the file open at the same time, whoever saves last will overwrite the changes made by the other.

Security is fairly limited. Remote users must use their e-mail address as their account names and can create passwords of their choosing. There is no enforcement of strong passwords, and you can make five attempts to guess a user's password. The system then locks you out for 10 minutes, and then you can try again.

For sensitive data, your best security is to password protect backups and not enable sharing of backup sets. Bear in mind, however, that passwords can't be retrieved if forgotten.

Net Net

Mirra Sync's ability to let you publish content to the Web is a very cool concept, and the product now offers much more disk space for the money than it did when first introduced a few years ago, when 80GB and 120GB models were the norm. The disk drives are parallel ATA, and the list price is US$499.99 for a 320GB model and US$599.99 for 500GB. But does it make sense?

Increasingly, programs and data are moving into the Internet cloud, not to the edges. Photo sharing sites allow uploading of photos for free or for a relatively small charge. SmugMug, for example, lets subscribers upload unlimited amounts photos for US$39.95 per year versus US$599.99 for 500GB of capacity on the Mirra Sync.

SmugMug won't allow you to share other files, of course, nor will it provide remote access to your files while you're on the road. However, there are risks in setting up a personal server that requires you to keep certain ports in your firewall open and that relies on a third-party service to authenticate and provide users with remote access to resources inside your firewall. More importantly, there are risks to having a server designed to publish to the public Internet also hold backups of all of your important data, not just that which you want to share.

In the business world, data for publication to users on the Web resides on a separate server that's isolated from the rest of the internal network in what security experts like to call a demilitarized zone or "DMZ." Furthermore, that same server would never be used to hold backups of other important business data. Why should your home- or small-office network be any less secure?

For those who enjoy the idea of directly publishing noncritical files such as photos over the Web, the risks are probably fairly small. Seagate suggests other applications, such as for a real estate office that wants to show clients photographs of properties for sale (although publishing them on a Web site might be easier for customers than having them log into the Mirra Web site). If you want to do so, however, my advice is to upload only the files you want to share and use another method for your data backups.