With the recent release of Dantz Development's Internet-savvy Retrospect Express 4.1, which joins Retrospect 4.1 and the BackJack Internet backup service from Synectics Business Solutions, I think it's safe to say that Internet backup has become a field - a step up from a trend, more stable than a fad, and nowhere near as big as an industry. I've been using these programs for a while now and have come up with some suggestions for how you can integrate Internet backup into your backup strategy. What will work best for you relates to how much storage space you have (or are willing to pay for) and how fast your Internet connection is.
Advantages of Internet Backup -- First off, let's briefly look at the advantages of backing up to a server on the Internet.
No need for additional hardware (although, unless Internet backup constitutes your entire backup strategy, you still need appropriate hardware for local backups).
Guaranteed off-site backup, which protects your files in case of fire, burglary, or natural disaster.
Integrated backup strategy for businesses with off-site employees.
Access to your encrypted backups wherever you can access the Internet (this might be useful to heavy travelers).
The main reasons suggested on TidBITS Talk for why people have decided against Internet backup are concerns about the reliability and longevity of an Internet backup service, the safety of sensitive information, and the length of time necessary to back up a large hard disk even over a DSL or ISDN connection.
Several Megabytes Available -- Most Internet service providers offer a few megabytes of disk space with your Internet account. Often people use this space for publishing Web pages. As long as this storage space is accessible via FTP, you can use Retrospect 4.1 or Retrospect Express 4.1 to back up a small number of important files to your Internet account. In this case, backing up only a few files via the Internet cannot form your entire backup strategy; you must perform backups to removable media as well or risk losing everything other than a few of your most important files. In addition, some ISPs don't back up their FTP servers, so they prefer that you don't rely on them for secure data storage.
Retrospect and Retrospect Express try to be too helpful in this situation. By default, both add new versions of files to your backup set, which is great with removable media, but which can quickly fill up a small FTP disk space allocation. My solution is to have Retrospect Express perform a Full Backup every other night. In Retrospect parlance, a Full Backup resets the storage set, replacing the previous contents. So, by doing a Full Backup every other night, I ensure that my backup set cannot grow significantly larger as I modify files. The drawback is that I may have only the most recent version of each file backed up. You can check the amount of space used by viewing the StorageSet summary in either program.
50 to 100 MB Available -- Let's assume that you have more disk space available. It's possible your business provides it, your ISP doesn't care how much you use within reason, or you're paying a backup service like BackJack or one of the Dantz Certified Internet Backup Sites (currently including Committed to Memory, Recover-iT, and Portland Communications, which is located in Europe). The fee-based Internet backup sites all currently charge by the amount of disk space you use; although the details vary, the rates are generally comparable. You can estimate between $15 and $25 per month to store 100 MB.
For most people, that much space will be roomy enough to store backups of all of your documents, preferences, macros, email, and other files that you can't easily reinstall. There's less need to back up large system files or applications, since you should have master disks. You could rely on Internet backup entirely in this situation, which makes sense for iMac users or people who don't create large files. In short, this level of Internet backup is perfect for most home users, who should look at either BackJack or Retrospect Express 4.1 (the full-fledged Retrospect is overkill).
The choice between Retrospect Express and BackJack is one of trade-offs. Retrospect Express is inexpensive and much more flexible and powerful than BackJack, but BackJack is free and easier to use because of its lack of selection flexibility. In Retrospect Express, you'll want to perform a Normal Backup most nights, but once every week or two, you should perform a Full Backup to reset the storage set to use less space. BackJack handles this situation more elegantly, since you can set how many versions of a file to keep and how many days to keep a file after you've deleted it. These BackJack features, in combination with built-in StuffIt compression (which is probably tighter than Retrospect Express's compression), help reduce the amount of data you're storing.
If you ever want to back up to removable media as well, Retrospect Express is a better choice, since BackJack can only back up via the Internet. But if you're hyper-concerned about the security of your data, BackJack's 128-bit encryption is significantly stronger than Retrospect Express's SimpleCrypt encryption.
You need at least a fast modem connection to the Internet since transferring this much data takes time, and you definitely want to run backups at night.
Unlimited Space Available -- Corporate users or people at large universities may have access to FTP servers with essentially unlimited amounts of space. In this case, you probably also have at least a 10 Mbps Ethernet connection to the FTP server, if not a 100 Mbps connection. The combination of massive space and fast network connection (anything less than a 1.54 Mbps T1 connection probably wouldn't work) means you could back up everything to the FTP server via Retrospect or Retrospect Express. In essence, the Internet backup set would act just like a tape backup set, and it would make a great off-site backup for a student (dissertations and similarly important projects should be backed up in numerous different places). You probably wouldn't want to pay to use BackJack or one of the Internet backup services because of the high cost.
In an organization large enough to have this kind of FTP space available, there might already be a centralized backup procedure in place that could include Internet backup. For instance, it might make sense to back up an entire department to a large FTP server using Retrospect, because Retrospect is smart about storing only a single copy of identical files on multiple machines. Thus, adding more computers to the backup (Retrospect can also back up Windows machines) might not significantly increase the size of the storage set if everyone uses similar applications.
Even if your files are being backed up already, it might not happen every night due to the sheer volume of data that needs to be backed up. In that case - especially if you don't trust the person or group doing the backups - you might consider your own Internet backup as a secondary backup, perhaps handling only files you can't easily reinstall on your own. An added advantage of your own backup is that it may be easier to recover a file from it than from a centralized backup.
Give It a Try -- I think Internet backup is here to stay. It might be a way for some home and iMac users to avoid buying an additional backup device and dealing with physical media, or it might prove to be excellent secondary backup of important files; either way, Macintosh users can now add it to their backup strategies. For a more detailed discussion of backing up in general, check out my article series on backups.