(NOTE : Article updated. Please read the final few paragraphs)

I decided to try an online backup service in order to better protect my really important data. This mainly consisted of my photo collection.

I was already using a set of hard drives to create backups some of which I kept at another location but it was difficult to keep these up to date.

Mozy and Carbonite seemed to be mentioned whenever the topic of online backup came up so I decided to give them a try.

I've tried both of them and here are my conclusions :

Carbonite
Computer Shopper magazine provided a six month trial. This was a brilliant opportunity to try the system out for a sensible length of time. The registration and install process was easy and within minutes I was uploading my photos to their servers. I started with small batches and gradually added more files over time.

The interface is great and really couldn't make the process any easier.

One important feature of Carbonite that you need to understand before you use it is that it does not backup certain file types by default. If you select a bunch of folders to backup it will not automatically include video and executable files. If you want them backed up you have to select them manually. This is clearly mentioned on the Carbonite website so didn't come as a surprise to me. Other people on the net clearly can't read as this is common complaint. RTFM.

For my photo collection this wasn't an issue.

What was an issue was Carbonite ignoring random jpeg images within my collection for no reason. It just would not back up some images. There was nothing I could do.

I contacted Carbonite support for help. I explained that some images simply were not backed up. Even the manual method didn't work. There were no error messages. Their support replied and asked me for a screen shot of the error. What error? I had already explained in clear English there was no error message. I think they were pulling the old "fire off a boilerplate response" trick.

Random files missing from my backups? No thanks. I un-installed Carbonite.

Mozy
Next up was Mozy. They offer 2GB of free storage with the option to upgrade to their unlimited service if required. Installation was easy.

The interface isn't as simple as Carbonite. This may or may not be a benefit depending on your software tastes. Mozy does however offer more configuration options including options for throttling the bandwidth it uses at particular times of day.

Mozy has no restrictions on file types so backs up everything you tell it to. It isn't quite as slick as Carbonite but actually works better so it gets my vote.

I am now half way through my photo collection and have signed up for their unlimited package.

If you need to recover your data Mozy can provide DVDs (for a fee) which would save you having to download the data from the web. After a catastrophic loss this might be the easiest way to get your data back.

So Mozy vs Carbonite? Mozy for me thanks.

A Note About Upload Speed
I've seen a number of people moan about the time it takes for Carbonite or Mozy to backup your files. It is always going to be limited by YOUR upload speed. Got 100Gb of files? It's going to take a while you muppets. If you can't understand the concepts behind uploading data you shouldn't be allowed a computer. Some people out there are moaning that their backups are slow while at the same time moaning it interferes with watching junk on YouTube. It's not magic!

A Note About Other Backup Strategies
Lots of people think online backups are stupid and advise people to just use external hard drives. That's great if those hard drives are no where near your PC when it gets burnt/stolen/destroyed/electrocuted. For most people when their PC gets stolen their backup will get stolen as well. Unless you are going to backup onto multiple hard drives at multiple locations you are at risk. Online storage reduces my chances of losing my family photo collection to almost zero. I backup to hard drives and DVDs as well :) If my house burns to the ground tomorrow my important data is safe.

UPDATE : I've just cancelled my Mozy subscription.

I installed a new DVD drive which stole my "E" drive letter temporarily so my data on my hard drive wasn't mounted by Truecrypt. Mozy decided that my data didn't exist anymore and all 33GB of upload data disappeared. When I rebooted and got E back Mozy happily started uploading it all again.

It might have been possible to get it back perhaps but that sort of spoilt the trust I placed in it.

Oh well, thats $4.95 I can save a month!

My recommendation? Backup your data yourself. Its the only way to be sure.