How safe do you feel?

Most people I know do not have any plan to backup their data. Somehow they put their trust to a piece of 3.5″ glass disc, spinning at 5400 times a second or more with a sharp metal spike fraction of a hair above it. Me? I like to spread my risk and backup my data, especially after suffering a total data lost about 12 years ago. As Alex Lindsay from the PixelCorps often says on podcasts, “Unless the data is stored in 3 different places, it doesn’t exist”. This may sound over the top but with all the online file sharing or storage services available it is actually pretty easy to have decent backup strategy with minimum cost. To achieve comprehensive backup coverage, it would definitely cost a few dollars.

Like computer security, any backup strategy should be constructed in layers. This applies to both time, location, and accessibility. Let me use my backup strategy as an example.

The least time consuming (in terms of setup and maintenance) backup component in my setup is Time Machine that comes with OS X. I setup Time Machine to backup to an external drive (more on that later) that is the same size as my main bootup drive and that’s it. Time Machine will then backup everything on the drive and updates the backup copy with any changes every hour. This provides the first layer in my backup strategy; files that are used most will always be backed up and available to restore quickly.

In the event of my bootup hard disk fails, I can restore from the Time Machine backup. But that can take a while given most hard disk is rather large nowadays. So to keep down time to the minimum, every week I also clone the entire hard disk to an external disk (separated from the one Time Machine uses). I use Carbon Copy Cloner for this and while it is not a ‘set and forget’ setup like Time Machine, it only requires 5-10 minutes of actual effort every week on my part to clone the hard disk. This copy will allow me to boot my Mac up from the external drive within minutes of any internal hard disk failure. At the most, I’ll have 6 days of data to catch up using Time Machine and that would not take long at all.

So I have two copies of my internal hard disk on two different external drives, e.g. data in two places. Pretty safe, right? Yes, pretty safe but not very safe. What if any of these two external drives fails? Then I can easily back to having no backup at all.

To mitigate that, the external drive that Time Machine uses is actually a Drobo. Drobo is a fully redundant disk array so data will be stored in a way that only all the drives fail at the same time in order to loss the data. This means my Time Machine copy is actually safer than just being stored on a regular external drive. The problem is that the Drobo drive is still sitting right where my machine is. What if someone break into my apartment and steals my computer, the clone external drive, and the Drobo? What if there is a fire in the building and all my computer equipment are lost?

For that eventuality, only an offsite backup will save my data. Again, time, location, and accessibility guide which services I choose to use. For files that I access and save often, I store them on Dropbox. It is ultra fast (way faster to sync to the cloud than MobileMe, for example) which makes it a pleasure to use. The free option let you store up to 2GB of data and it is more than adequate for my day-to-day data. This also have the added advantage of allow me to access files on different computers, e.g. my work laptop. For files that I need less often and larger (for example, video files that I want to share online), I store them on MobileMe’s iDisk. Data syncing is nowhere as fast as Dropbox but it provides more data storage.

I also use a separate online service to store my code. cvsdude provides online storage of code using CVS or Subversion. I also use GitHub for my latest code project. Eventually all of my code will be stored on GitHub once my subscription with cvsdude expires.

But what about all the music, photos, and videos files that I own? Their large size make it difficult to backup to the cloud. Right now I store all of them on the Drobo so they are protected against disk failure but that means they exist only in one place (strictly speaking more than one copy is stored by Drobo). To guard against total loss, I am currently in the process of using Mozy to backup all of the media files which come to about 600+GB. The MozyHome Unlimited plan is not free but it will be tough to ask someone to provide that amount of backup storage at no cost! The issue with Mozy is the time requires to upload that much data to their data centre. Even with a decent upload connection of ~2Mbps I am expecting the upload to take at least 3-4 months to complete.

To recap, here is where my data exists:

1. Files (e.g. documents, emails, applications, etc.) – Internal hard disk, Time Machine on Drobo, clone on USB external drive = 3 places
2. Important/Frequent use documents (subset of #1) – Internal hard disk, Time Machine, clone drive, Dropbox, MobileMe’s iDisk = 4 places
3. Code files – Internal hard disk, Time Machine, clone drive, MobileMe’s iDisk, cvsdude/GitHub = 5 places
4. Media files (iTunes library, iPhoto library, iMovie Events & Projects) – Drobo, Mozy = 2 places

Am I crazy? Ask me again when you have a hard disk failure and want some advice on how to recover your precious data.