Archive for January, 2012

7 facets of a good Mac backup strategy


January 23rd, 2012

I’ve been studying the computer backup industry for 3 years now and I’ve been selling my own online backup product, Arq, since February 2010. I’ve seen and heard lots of different approaches to backing up one’s computer. Here are some backup lessons I’ve learned.

1. Assume your hard drive will fail very soon

Expect imminent disk failure no matter how old or new your hard drive is. The other day a customer sent me email saying Arq was reporting input/output errors. I told him it was probably a hardware problem and he should replace his hard drive ASAP. He said it’s an SSD that he installed 2 days ago, so that can’t be it. A few days later he wrote back saying the SSD was the culprit.

SSDs in my opinion are worse than spinning drives because they seem to fail catastrophically more often. Spinning drives often fail more gradually, giving you a chance to copy your data off, which is especially good if you haven’t been doing backups — but you are doing backups, right?

2. Automate it

Any backup approach that requires you to remember something has one big problem: you’ll forget. If you have to plug in an external hard drive for your backup approach, you won’t do it. At least not often enough.

3. Keep it simple

Choose simple backup processes to minimize the opportunity for error. Apple’s Time Machine is a great example of a simple app. Arq asks almost no questions — the defaults are fine. SuperDuper is just as simple — you just click one button and it makes a clone of your hard drive. All of these apps have lots more options, but you can safely ignore them.

4. Use multiple backup systems

This goes against the “keep it simple” advice, but counting on just one backup strategy is risky. When it comes time to recover from failure, you want as many opportunities to get your stuff back as possible. You don’t want to wake up one morning to a disk failure and then find out that you’d accidentally deleted your one backup app 6 months ago and you’ve lost 6 months of work. Or find out that your one online backup provider lost your data, or disappeared altogether.

Speaking of online backup: make sure one of the backup systems you use is off-site, to protect against theft, fire, lightning strike, flood, etc. For example, rotate your clone backup drives keeping one at the office (if your office is in a different location than your home!) or use an online backup service. I use 2 systems — one local and one off-site (explained below).

5. Minimize recovery time if possible

If you need to recover your entire computer from a Time Machine backup, you’re supposed to use Apple’s Migration Assistant app. Migration Assistant can be very slow however, especially when restoring from a Time Capsule over the network. If you have a clone of your hard drive made with an app like SuperDuper, you’ll be back in business in a minute — just plug the clone drive in, hold down the Option key, and boot your computer from the clone.

One potential downside of recovering with a clone is that in your haste to get back to work you may forget all about the fact that you’ve got no clone anymore! This can easily happen if you use a desktop computer — you won’t even notice that you’re running off the external hard drive.

At your earliest convenience you need to get another hard drive and clone to it, in case your clone fails. Having multiple backup systems helps mitigate this problem too.

6. Protect against corruption and “user error”

One of your backup systems should be a “versioning” system. Time Machine and Arq are 2 examples of this. They keep hourly backups of your files for the past 24 hours, daily backups for the past month, and weekly backups until they reach your storage budget (Arq) or the target disk is full (Time Machine).

Clones of your hard drive are great, but they’re only the latest version of your stuff. If a file becomes corrupt, the next time you clone your hard drive you’ll replace your old clone’s copy of the file with the new corrupt one.

One of your backup systems should keep multiple copies of your files over time to guard against corruption as well as the occasional what-was-I-thinking-when-I-deleted-half-that-document moments.

7. Avoid services whose interests aren’t aligned with yours

If you’re choosing an online backup provider, pay close attention to the data retention policies, especially with the “unlimited” offerings. Backblaze, for instance, will delete backups of your external drive if it hasn’t been connected within the past 30 days.

Also consider who has access to your stuff. With Backblaze you can pick your own encryption password, but if you need to restore your stuff you’ll have to give them your password; they decrypt your stuff and leave it in an unencrypted zip file on their servers; if you have them send you a disk with your stuff, your files will be sent through the mail unencrypted on that disk.

Also, any service that offers web access to your backups obviously has the ability to read your stuff (so that they can serve it to you through a web browser).

My Approach

I do all my work on 1 laptop (a MacBook Pro). I clone my laptop’s 2 internal hard drives (an SSD plus a spinning drive) using SuperDuper whenever I think of it. Arq backs up hourly all day long, from wherever I am, as long as there’s an internet connection. My computer doesn’t really go anywhere for very long that doesn’t have an internet connection, so this works for me.

If my SSD boot drive fails, I can’t boot from my Arq backups in S3, but I can get up and running quickly from the clone (which will probably be out-of-date) and then replace my key files with the latest versions from my Arq backups.

I feel good about my data at S3 not going anywhere. It’s in my own S3 account, and Amazon promises 99.999999999% (that’s 11 9s) of durability over 12 months.

In the worst case, if both my computer and my clone are damaged/lost/stolen I can download all my stuff from S3 using Arq, but it’ll take a while.

(SuperDuper and Arq are Mac-only. If you’re on Windows, you could try Acronis True Image for cloning and CloudBerry Backup for backup to Amazon S3.)

I should probably add a third option. Any suggestions? Send me email or post a comment!