Everybody likes Mozy--except me, Part 1

Online off-site backups are a good thing. Mozy may not be your best choice, however. Part 1 of two blog posts.

Michael Horowitz

Michael Horowitz wrote his first computer program in 1973 and has been a computer nerd ever since. He spent more than 20 years working in an IBM mainframe (MVS) environment. He has worked in the research and development group of a large Wall Street financial company, and has been a technical writer for a mainframe software company.

He teaches a large range of self-developed classes, the underlying theme being Defensive Computing. Michael is an independent computer consultant, working with small businesses and the self-employed. He can be heard weekly on The Personal Computer Show on WBAI.


Michael Horowitz
6 min read

For a company in the boring business of online file storage, Mozy gets more than its share of press coverage, and from what I've seen, it's all been positive. Mozy attracted attention back in December 2006 when they started offering unlimited file storage for $5 per month or $55 per year (rounded off).

The first Mozy review I ran across was by Walter Mossberg in The Wall Street Journal ("These Services Make Backing Up Your Files Safe and Inexpensive", December 14, 2006). He liked Mozy, so I spent some time reviewing them for a class I teach on backing up your computer. My opinion differed from Mr. Mossberg's, not for the first time.

Then in January 2007, David Pogue, writing in The New York Times, also liked the service ("Fewer Excuses For Not Doing A PC Backup", January 4, 2007). I blew that off too. But a couple weeks ago the tech Web site Ars Technica published a review of online storage providers by Joel Hruska that recommended Mozy as the best of the bunch ("Online backup solutions: a review", July 16, 2007). For me, that was the final straw. Time to speak up.

The good reviews

In his review Walter Mossberg compared Mozy to Carbonite, another online storage company. He found Mozy "easy to set up and easy to use" and seemed impressed that using the Web-based interface he could restore files on a Macintosh computer. Security is an obvious concern with off-site storage and addressing it he said, "Both companies encrypt the backed-up files and say they don't view them." Finally, he notes that "you can back up multiple computers--but you have to pay extra for each additional machine."

Pogue also found Mozy more flexible than Carbonite, citing as an example the fact that backups can either be continuous or run at specified times and dates. He pointed out that Mozy can back up only changed portions of files, and he liked that you can review 30 days of backups (more on this below). His only criticism was minor, he felt that Mozy might not be the best choice for beginners as some of its options are "novice-hostile."

Writing for Ars Technica, Joe Hruska reviewed Xdrive, Backup/PC, Mozy and Carbonite and concluded: "Of the services we tested here, Mozy Online struck the best balance between functionality and flexibility and is our overall top pick for an online backup service."

My opinions

To start with, I don't like any backup service whose software has to run constantly in the background. The more software running on a computer the greater the chance of something going wrong. I prefer a backup scheme where the backups happen on a schedule and/or on demand. Thus, 99 percent of the time there is no backup software running. I don't like my computer doing stuff without me knowing about it.

And, if I had to go with background software that never shuts down, my preference would be for a mature product. Something that's at version 11 and has been around for years. Mozy is a relatively new company; it was founded in 2005. In December of 2006 when Mr. Mossberg wrote his review, the Mozy application software only ran under Windows XP. Now it also supports Windows 2000 and Vista and they have Mac software in beta testing. This is all too new for me to trust it with something as important as file backups.

Mr. Mossberg's description of the Web-based interface failed to point out that it can't be used for making backups, only for restoring files. As he said, Mozy charges extra for each additional computer that you back up from. The online backup service that I use, which I'm not going to mention both because it's not perfect and this blog is not an ad, allows me to back up files from an unlimited number of computers using their Web interface. This should be a prerequisite for any online storage service you may be considering.

Big sin

Mozy's biggest sin wasn't mentioned in any of the reviews. (Doesn't anyone read the fine print?)

An obvious reason for making backups is to be protected from accidentally deleting files. If your fingers slip while typing, you can wipe out dozens of files and not realize it. Or someone else using your computer might delete them. Or there may be a glitch in the file system and Windows loses track of some files.

If you delete a file by accident and don't notice it, Mozy will delete the backups of the file too. I kid you not.

This is a quote from Mozy.com (as of July 29, 2007): "If you delete the working copy on your machine and then run a backup, Mozy will assume that you no longer need a backup copy, since you got rid of the working copy, and will mark the file to be removed from our system in 30 days...After 30 days, you cannot get these files back."

Pogue made a bad thing seem like a good thing when he wrote: "You can view 30 days' worth of backups, too--a feature that prevents you from deleting a file from your PC accidentally and then finding its deletion mirrored in your latest backup." Mr. Pogue is assuming both that you know a file was deleted by accident and that you try to recover it within 30 days. But if you are not aware that a file is missing until 31 days after it disappeared, it's gone. With my online backup company I could accidentally delete a file, not know about it for years and still be able to recover the last backed-up copy.

Perhaps you know someone who has had to reinstall Windows? Or had their laptop computer stolen? With Mozy there is a chance it may treat missing files as being deleted on purpose, and delete the backups in 30 days. I have no idea how likely this is, but if something can go wrong, it will. And again, there's that issue of relatively new version 1 software to consider.

Why does Mozy do something that seems so wrong? I think I know.

In their free service Mozy offers 2GB of storage space to anyone who feels like asking for it. The less space someone uses, the better it is for them. In their paid service, Mozy offers unlimited storage for $55 per year. Here, too, the less space a customer uses the better it is for Mozy. In this context, it makes sense for them to delete as many files as possible. It's a natural outgrowth of their business model.

In contrast, Mozy's competitors charge more as their customers use more storage space. It's reasonable to assume that these companies make more money the more data they are storing. Thus, they are not motivated to delete files. In my opinion, you're better off using a company with this business model.

Mozy customers are, in effect, trying to get something for nothing with unlimited storage for only $55 per year. It's too good to be true.

I'm far from done. More tomorrow...

Update. February 9, 2008. In an attempt to generate commissions someone made a comment to this article suggesting that mozyonlinebackup.com offered impartial reviews. It does not. The site is run by John Pontillo of Fishkill, New York. That the links to Mozy look like
is a giveaway of the true purpose of the site - generating commissions.

See a summary of all my Defensive Computing postings.