This week I have been testing the various online backup services, both paid and free, and here’s a summary of how these service compare against each other.

Why use an online backup service?

While it is easy to create a local backup of your computer, the physical media where you are storing the backups, like the DVDs or external disk, may not be very reliable in the long term. The other disadvantage is that local backups don’t always happen in real-time.

It is therefore recommended that you switch to an online backup service – these are inexpensive and will automatically copy your computer’s data over the Internet to a more secure off-site location (aka the data center) in near real-time without your involvement.

Online Backup Services with Free Storage

If you only have a limited amount of data (< 2 GB) on your computer that you want to store in the cloud, any of the following backup services should solve your problem without you having to shell out a penny.

All the above online backup services (except for SkyDrive) work in a similar way – you download a small client to your desktop, mark the local folders that you want to backup online and the tool will automatically monitor and upload files from these folders to the cloud. Once your files are backed up, you can also access them online except in Mozy.

Of all these services, my favorites are SugarSync and ZumoDrive. They offer almost an identical set of features and are extremely easy to configure. SugarSync is available for Mac and Windows while ZumoDrive also offers a Linux client.

While Dropbox is also an awesome service for file synchronization and online backup, it has one major limitation – it will only backup files and folders that are placed inside the Dropbox folder. Hopefully this will change in future versions.

Subscription Based Online Backup Services

When 2 GB is insufficient to store the massive number of photographs, emails, documents and other important files that are piled up on your hard drive, you can go for a subscription based service. Here are some good options along with their pros and cons.

1. Backblaze (tour) – The true ‘set it and forget it’ backup service

• Extremely easy to setup. The service will automatically backup your entire computer excluding folders that contain the OS and your applications.
• If you create a new folder on your computer, you don’t have to remember to add it to the backup queue.
• The option to restore files from the backup could have been a bit simpler.

2. Carbonite (tour) – Makes data recovery really simple

• Colored dots on your files and folders indicate the status of your backup at a glance. No dot means the file is not selected for backup.
• You can remote access your backups from anywhere using the browser and there are apps for iPhone and BlackBerry.
• The restore function in Carbonite is done pretty nicely and you can recover files using Windows Explorer itself.
• Carbonite’s web interface is clean but their desktop client looks old and a bit untidy.

3. Mozy (tour) -  The original cloud backup service

• Mozy will automatically group your files and folders into “sets” like documents, emails, photos, music, etc. so it becomes easy for you to select stuff that you want to backup online.
• In addition to online backup, the more recent version of Mozy can also back up your data to an external disk.
• Mozy offers quite a few easy ways to restore files from the backup.

4. iDrive (tour) – For quick and easy backups

• When you start iDrive, it offers a folder tree of your computer – just select the folders that you want to backup online and you’re done.
• You can also add files and folders to the backup queue with a simple right click inside Windows Explorer.
• You can restore data through the iDrive desktop client. Individual files and folders can also be recovered from iDrive’s website.
• Their Family plan can help you backup multiple computers to a single IDrive account.

5. CrashPlan (tour) – One backup service for all platforms

• With CrashPlan, you can easily backup your files to multiple locations including the cloud, to another folder on the same hard-disk, to other computer on your home network or to any other Internet connected computer (social backup).
• The desktop client is intuitive and won’t confuse you with a plethora of options.
• CrashPlan is among the very few online backup services that’s available on all platforms including Windows, Mac and Linux.

6. Jungle Disk(tour) – Metered online storage

• Jungle Disk uses Amazon S3 for data storage.
• You can use a single license to backup multiple computers.
• Jungle Disk supports Windows, Mac and Linux.

7. SugarSync (tour) – Access your backups from any mobile device

• SugarSync works in near real-time and will immediately back up any file changes that are made in one of the monitored folders.
• You can easily access your backups over the web or from any of your mobile devices through apps.
• SugarSync is not integrated with Windows Explorer and therefore it is a bit cumbersome to add new folders for backup.

8. ZumoDrive (tour) – Simple and elegant

• ZumoDrive is extremely easy to configure – just right click any folder on your computer and add it to the ZumoDrive cloud.
• Restoring files from ZumoDrive may involve some effort. It offers ZIP archives of your folders that you’ll have to manually extract to the right locations.

Online Backup Services Compared

The following chart compares the cost, available storage and other essential features of all the previously mentioned online backup services.

Which Online Backup Service Should You Use?

If you are looking for an extremely simple way to backup your entire Mac or Windows PC without having to select individual files and folders, go with BackBlaze. It offers unlimited storage and requires no configuration but restoring data from BackBlaze is not very convenient.

SugarSync is another brilliant option for creating online backups as it works across multiple computers (and platforms) and you can access your data on a variety of devices. However, if you have loads of data to backup, SugarSync can get a bit pricey.

The backup service that has impressed me the most is CrashPlan – it’s available for Mac, Windows and Linux. What’s unique about CrashPlan is that it also can create local backups on other computers that are either owned by you or your friends. Thus data restoration will become extremely fast in the event of a hard disk failure because you won’t have to download backups from the Internet.

The downside with CrashPlan is that it doesn’t offer web access to your backups. If you see this as a limitation, go with Carbonite. It integrates very nicely with Windows Explorer, you can backup any file or folder with a simple right-click and all your files can accessed over the web anytime, anywhere. Data restoration is also easy with Carbonite.

Related: Photo Backup Services Compared