The best value hard drive for a RAID5 setup

EDIT: Here is the spreadsheet so you can edit with your own specs: link

I’ve been wanting to rebuild my fileserver/NAS box which has 500GB of movies, music, and pictures. Its got to be fast and cheap, and I also wanted to play with linux RAID. After doing some reading, a RAID5 configuration seemed to be my best bet. I’m also going to go ahead and upgrade the space to about 1TB so I don’t have to worry about expanding for a while. I decided to make a little spreadsheet to figure out which would be the most cost effective way to build a RAID5 array totaling 1TB of usable data. I’ll share it with you.

Goals: Have about 1TB of usable space for as cheap as possible.

As you can see, the 320GB seems to be the best value at or around 1TB. Even though you lost a few gb over the other 3 options, the total cost of the hard drives seems much more affordable. The 250gb is similar in price and gets you a little more space, but the more hard drives you add, the more you risk hard drive failure. As the quantity of hard drives in your box increase, the rate of failure increases. The chance of 1 out of 5 disks failing is greater than 1 out of 4. Additionally, increased temperature, losing an hdd slot, and more stress on the PSU makes 250GB’s really not worth it. Not to mention they are 3 cents more expensive.
Now lets prepare for the future. I already upgraded my 500GB server to 1000GB. What happens when I want to upgrade to 1500GB? Obviously hardware costs will be a little different when that time comes, but just for fun, lets put it on paper.

And 2000GB?

Again and again, the 320GB is best in value. Thats why I went with some WD 320GB RE’s and didn’t look back.