I was greeted by a stream of loud and high pitched beeping from my server when I returned home on Friday. Panic set in that very moment, but it didn’t last. Within seconds, I had ascertained the source of the problem, and although it was worrisome one, it wasn’t the end of the world, at least not quite yet.

My first thought was “Doh! Server’s overheating!” but cooler minds prevailed. If the server had indeed overheated, it would have shut itself down instead of beeping madly, and it was still responsive. Well, I thought, the only other thing in the server that had an embedded beeper aside from the motherboard was the RAID controller card, so it had to be that. I have a RAID 5 array, consisting of four hard disks set up on the server, and a quick check showed that the status of the array was ‘critical’, with one drive failing.

In a RAID 5 array, a number of similar capacity drives are used, with the equivalent of one of the drive’s capacity being used for storing parity bits. Thus, a RAID 5 array can sustain the loss of one drive before data is irrecoverably lost.

So what did I do? I ran out the next day, bought myself a new 500 GB drive for SGD$87, replaced the failing drive, and a disaster that would have involved a very painful loss of data was averted. Since my RAID controller (a rather dated Highpoint RAID 1740) supported online rebuilding, no downtime was incurred at all.

Lesson to be taken from this: Data is precious and you never know when a drive could fail on you. If your entire life resides digitally on your computer, make sure you have a backup plan.