Digital data is growing in importance not just in the workplace, but also at home. We correspond by email, take digital pictures and videos, and maintain digital music collections. All this valuable digital content and more is stored on your computer's hard drive. Hard drives are delicate mechanical devices with a finite lifespan. A quick online search suggests that a typical lifespan for a drive is somewhere between three and six years. So a drive will fail eventually. Are you prepared for a crash?
I was given the opportunity to answer that question myself when my hard drive crashed recently. I certainly wasn't expecting it: the drive was less than two years old. Was I prepared? The short answer is not nearly enough.
I had regularly performed backups of my most important data files to CD once every two months. So I did have a five-week-old backup that contained all my emails, my development projects (including my Subversion version control repository), my writing, and other important personal documents. This backup did not include my digital photos, but I had recently printed a set by my typical process of burning them to CD. I also had a data CD that contained a significant subset of my music collection, plus a variety of audio CDs. Nothing else was backed up. Fortunately, luck was on my side. After some investigation, I discovered that my hard drive had only suffered a partial failure. Using the program Recover Lost Data, I was able to recover some of the files that weren't part of my backup, or that I had modified in the five weeks since my last backup.
Despite my foresight in making backups and my luck in recovering files off the damaged drive, recovering from this crash was a painful, time-intensive process. I permanently lost many of my digital photos and personal videos. I had to reinstall and reconfigure all the applications I regularly use. Firefox was especially painful: I was unable to recover my long list of Firefox extensions, so I had to search online to try to remember which ones I regularly use. I also had to download all the development libraries that I use in my personal development projects. Fortunately I use only a few commercial software products - the rest is open source - and had the necessary license information to install them.
Even before I started this recovery process, I knew that it wouldn't be easy or quick, and I decided that I didn't want to go through this experience again. I needed a better backup strategy. I wanted to be able to back up all my applications, including configuration information, as well as all my data files. Since some applications store configuration information in the windows registry, this essentially requires backing up the entire drive. Doing this would allow for a seamless recovery from a crash. I also wanted backups to be done as often as possible and require minimal effort on my part. This might sound like a tough set of requirements to fulfill, but I already knew of a solution. Disk mirroring or RAID is when the same data is stored on multiple physical drives. RAID 1 is the simplest RAID configuration, consisting of two physical drives that are treated as a single logical drive. If one drive fails, the system can continue to operate using the remaining good drive without any loss of functionality or data. I first heard of RAID from an article by Joel Spolsky, in which he writes about deciding to switch all non-laptop machines in his company to RAID after an experience with a hard drive failure wasted at least a day of his time, even with daily backups available.
Like Joel, I decided I must have a RAID 1 configuration for all future computers. Rather than replace the drive in my existing computer, I went shopping for a new system. But apparently my conclusion about the value of RAID isn't shared by the average consumer, since none of the big-name retail stores I checked offered RAID as an option, even in their customized machines. My continued search led me to Dell, which offered RAID 1 as an optional extra (called DataSafe) on their Dimension 3100 model. I was surprised how cheap the RAID 1 option was: it cost only a little more than the cost of the second hard drive. So now I sit typing this article on my new Dell computer, knowing that my data is instantaneously being written to the two hard drives inside. I no longer need to worry about hard drive crashes, because I'm fully prepared.
Are you prepared for when your drive crashes? When I mentioned my hard drive crash to my coworkers, I was surprised by how many of them indicated that they had absolutely no backups. A few mentioned that they didn't store much of value on their computers, so a crash wouldn't bother them. But a growing majority of people do have valuable data to protect, and I think RAID 1 is the best option to do so. I'd like to predict that RAID 1 will eventually become the standard configuration for home computers, but that may be a little optimistic.
Where I would like to see RAID 1 as a standard is in the workplace, where a cost-benefit analysis clearly favors its use. And I'm not talking servers, but individuals' workstations. I've never worked at or heard of a company besides Joel's that provides RAID-configured machines to employees. Even if all important data is stored on network drives or in a version control repository, a drive crash still means time wasted by the employee waiting for a new drive, plus time spent reinstalling and reconfiguring the applications. And how many people don't keep at least a few important files on their local hard drive, which are almost never backed up by IT departments? Even a few hours of time wasted by a crash covers the cost of the RAID configuration for that machine, and I expect it is normally days of work lost or wasted by a crash. So I think RAID makes sense economically, and not just for developers but for executive and administrative staff as well. It pays to be prepared.
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