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How Often Do You Replace Your Hard Drives?
Telemachas asks: "I recently purchased a Dell P4 2.8 GHz swap meet computer with a 200 gig hard disk for a good price and all is working fine. It does not seem prudent, however, to trust my data on a swap meet item. For another @ $ 75.00 each I can purchase new 200 gig HDDs. I would also like to do my first RAID system. I am now wondering how often, if at all, do Slashdot readers replace their HDDs?"
I replace my hard drive when the S.M.A.R.T. info starts to signify problems, such as too many relocated sectors.
As I've already seen a couple of people say, don't preemptively replace your hard drives.
Allow me to add: Here's why.
Hardware failure rates follow a curve on average. They fail a lot after initial purchase, then slope down to their minimum after a couple of [relevant time periods] (probably "weeks" or "months" for hard drives, varies by what kind of thing it is), then slowly slopes upwards again.
(Please do not miss the phrase "on average". Certain specific flaws can cause a certain product line to have unusual characteristics, like a sudden spike at six months or something. However, unless you somehow figure out a way to guess which hard drives are going to have such failures in six months when it's pretty amazing for the exact same hard drive to even be on the market for six months, the fact that these things can theoretically happen can't have much impact on your decisions. After all, if you knew that was going to happen, you'd just plain not buy the drive, period, regardless of the argument in this post.)
Therefore, if you've got a "burned in" drive, you will be replacing a known-high-reliablility component with a component with a lower expected reliability. (I use "expected" in the probability/statistics sense here.) Unless you've discovered that you do have one of those funky products that all die in ten months, this is a bad move on average.
I replace hard drives when they fail. I try to act as if they could die at any minute, although I fail.
(But I try to get better. I'm in an all-laptop house, so it's difficult to have the convenience of an integrated backup solution and an automated, unforgettable script. However, with the recent Linux kernels finally supporting my SD card reader, I've gotten a high-capacity, slow, cheap SD card to stick in the previously-useless slot and I have an rsync now backing up the files I'd cry if I lost every hour. Sure, 1GB can't backup my entire system but most people's "cry if I lost it" datasets would fit into that. (Yes, there are exceptions... but if you're one of them, you've already got another back up solution in place, right? Right?))
There's really no replacement for backing up your files.
RAID 5 (or mirrored RAID, if that's your favorite flavor) protects against a single hard drive dying. But if the RAID card dies, you lose everything, especially if it's a proprietary card that's hard to find (more likely on a personal server); I've tried interchanging 3ware controllers and Highpoint controllers, and they couldn't read each other. Additionally, if more than one drive dies, you lose everything. Or, if there's some other problem (you know, the one you didn't think about before you setup the RAID) and the array gets corrupted somehow... well, you lose everything.
RAID can be a good supplement in addition to regular backups, but it's not a complete replacement.
Just a tip on the power supply sutuation. Spend a bit of extra cash and get a name brand one. The fans are quieter and the lifetime is a great deal longer plus they are generally a lot more efficient.
I'd always stinged out on the power supply but ever since I took the plunge and got a good one I'll never go back.
Except that raid 0+1 can't be implemented with 2 drives, it requires a minimum of 4.
Everything that's critical (and not so secret) goes as soon as possible on a backup CD/DVD (the more the merrier), on other home/office computers, even on memory sticks or whatever other removable media you might have at hand... and if possible, also some remote (and remotely accessible) location.
Um, if you have a 20-40 GB drive and don't fill it up and only have a CD burner that might be a solution. The best affordable solution for most people is to buy an external USB drive enclosure and a couple of HDs. Last Christamas, my mom gave me that 250GB drive and enclosure was only about $150 from tigerdirect. I used to trust CDs/DVDs for backup purposes, but I've been burned by bad copies of the CD/DVD not working on other machines. It may be slightly more expensive for the HD solution, but you just don't have to worry about it working unless all your backup drives fail, which is unlikely.