The 8 most common data loss disasters - are you protected against them?

Everybody knows that you're supposed to back up. But what are you actually protecting yourself against? Are you actually protecting yourself against it? There are four common backup destinations which I'm going to consider:

Your computer - backing up to a different folder
Your computer - backing up to a drive on your computer
Data center backup - backing up to a data center like Amazon S3, a hosting account FTP server or servers run by a service that specializes in online backup like Carbonite.
Another computer - either a friend's or colleague's computer, a colleague's computer or a stranger's computer. Most systems of this type encrypt the data being stored, so there is little risk of it being read by them, either.

1. Normal hard drive failure

By far and away the most common cause of data loss is hard drive failure, and if you're covered against this, your chances of losing data go from nearly certain to low (ish). Hard drives are fickle machines and will fail with 100% certainty eventually. Carnegie Mellon ran a study which examined annual replacement of hard drives and found that annual replacement averaged between 2-4% a year and up to 13% on some systems.

Are you protected by...?

Backing up to a different folder on on your computer - Probably not. Roughly half of drive failures render almost all of the data on the drive unrecoverable, except through expensive forensic analysis.
Backing up to a different drive on the same computer - Yes. The chances of both drives dying of natural causes at the same time are low.

Shared drive/network drive - Yes, same as above.

Online storage service? Yes. Though their drives will fail just as often as yours, it's very unlikely that your backup service's drives will fail at the same time as yours. Additionally, most services store replicated data.
Friend's computer / Stranger's computer? Yes.

2. Accidental overwrite

The second most common cause of data loss is caused by accidental overwrite of data. This is often caused by user error - for example, opening an important document, deleting everything in it and re-saving. Although most operating systems give you protection against accidentally deleting a file, but if you or another application overwrites it, you're on your own. Examples:

Are you protected by any of the above? Yes, with all of them but only if you use versioned backup.

3. Robbery

Your house is broken into, and thieves steal your computer. Where are all your priceless memories stored? Example:

Yesterday evening, Craig's apartment was robbed in Brooklyn. He lost his laptop and camera and expensive DSLR lenses and a slew of other belongings. I lost my new MacBook Pro (my birthday present to myself) and my Canon G9. I had a lot of personal information on the laptop invoices with my bank number, blog posts, journal entries. They also took all the hard-earned money from my summer of stoop sales $1500 in cash that I was going to deposit today. But worst of all, they took my 500GB backup hard drive, my netbook with another backup of my photos and my 32GB flash card with the 3rd backup of my photos. All of these were in different places in the apartment, and all are gone.

-- Legal Nomads.com

Are you protected by..?

Using an online backup service? Yes. In fact there are online backup services with thief protection built in.
Backing up to an external/network drive? No, it's likely that the thief will steal that as well, as happened to poor Jodi.

4. Malware / Virus infection

While most malware focuses on turning your computer into a botnet or trying to steal your valuable data (e.g. credit card numbers), some actively corrupts or deletes data. While you should protect yourself by running anti-malware/anti-virus software and being vigilant about what you download from the Internet, you can't protect yourself 100% against this. Stories:
http://answers.yahoo.com/question/index?qid=20110407214906AAEH4fU
Are you protected by...?

Using an online backup service? Maybe. There are two additional risks here - one, you may find yourself backing up the malware as well as your data, and losing everything again once you restore it. Two, you may find that your corrupted or deleted data has overwritten your 'clean' backups. Having an online backup service with file versioning will help with this.
Backing up to an external/network drive? Yes, if you are backing up to a network drive and using software that has file versioning. No, if you are backing up to a USB connected drive - the malware can easily corrupt or wipe your data.

5. Fire and flood

Your office is burned down or flooded. Insurance can cover the cost of buying or rebuil ding another house, but insurers will almost never cover costs incurred through data loss. Some data can't be replaced anyway. Stories:
It has been wryly said of computers that they work best when not on fire. Unfortunately, Pelindaba Lavender, a fully-integrated lavender planting, harvesting, and value-added product manufacturing firm based in Friday Harbor, WA, suffered a catastrophic fire on May 31, 2009. In addition to wiping out the company's offices, manufacturing facilities, and most of its harvested inventory, the flames consumed the company's Macintosh server.
http://mozy.com/success-story/pelindaba-lavender
Are you protected by...?

Using an online backup service? Yes, offsite backups are the only real protection against fire.
Using an external/network drive? No, if your house burns down or is flooded, both your computer and your external drive will likely be lost too.
Using an external drive locked in a fireproof safe? Again, likely not. No fireproof safes exist that can withstand more than 4 hours in a blaze.

6. Power surge

This occurs in 4% of all data loss stories.

Are you protected by...?

Using an online backup service? Yes, your service provider will likely be on a different electricity grid, so won't face. Additionally, nearly every data center has protections against power surges that most homes do not.
Using an external/network drive? Yes, if you disconnect your drive after each backup. No, if you leave it plugged in all the time.

7. Sabotage

An employee or family member could sabotage your data.

Story:

The bookkeeper of a small shipping company had been systematically embezzling funds from the company she worked at for almost 2 years. When the boss began suspecting foul play, the bookkeeper quit but not before covering her tracks by deleting certain critical records from the accounting computer.

-- http://www.drbackup.net/blog/online-backup-nabs-crooked-bookkeeper/

Are you protected by...?

Using an online backup service? Yes, provided your backup service keeps deleted files and file versioning on record. No, if backups are overwritten and deleted files are removed.
Using an external/network drive? Yes, provided your network drive and backups are inaccessible to employees and B) your backup software stores revisions and deleted files.

8. Silently broken backups

Your backup software whistles along without complaint and claims to be backing up your data, but is it? Maybe not.

Are you protected by...?

Using an online backup service? Not unless you test your backups. You can check failed restoration stories, but this is a poor substitute for testing restoration yourself. Unfortunately, online backup services can take a long, long time to download a lot of data, so testing a complete restoration is extremely difficult. Testing the backup of a few gigabytes of your most important files is easier, however.
Using an external/network drive? Not unless you test your backups. This is easier than with online backup software, as your data will be closer to you.

Tomorrow, I'll be writing about

the 5 data loss risks you might worry about but shouldn't.