Terastation Drive Replacement

February 26th, 2008

Back in 2005, i bought a Buffalo Terastation 1TB NAS (Network Attached Storage). Basically its a backup device – a mini-computer box with 4 harddrives, each 250GB, or 1TB total. Last week one of the drives died after a power outage (we get a lot of outages on san jose ave), and today i fixed it. However, it wasn’t that easy – I spent over 3 hours on it – when it should have taken less than one. So i’m just gonna note a few things so the next guy might have it easier. Now here’s where i’m gonna geek out, so all non-geeks .. move along.

When i first setup the terastion, i did a RAID5 + RAID1 – that means i got a 750GB partition out of my 4 250GB drives. So if any one of the four drives dies, i don’t lose my data. I just pop in a new drive and rebuild. Easy. This worked great for 3 years, never had to replace a drive. Every now and then we’d lose power and when i powered on my terastation, it would take 1-2 days to check the disks before we were good to go.

Last week Terastation would not recover – it would boot up for a minute, do disk check, then turn off (power light was off). However, each of the four drive status lights would stay red, with disk 3 blinking red. After reading the manual, I decided to replace disk 3. I also read the wiki FAQ, so i knew i could replace with any same-size or bigger drive. I did this, spending almost 45 mins opening the terstation up, switching the drive, and putting it back together. Turned it on, and it stayed on. Yay!

So now all i had to do is connect to the web manager interface and “rebuild the raid array”. Once i logged in, it said Raid array 1 error – i clicked it, and I’d get to array 1, and it listed disk 1, 2, 3, 4 .. but the checkbox to disk 3 was greyed out. I spent a while looking through the web pages and decided something might be wrong with my new disk. I turned it off, took the thing apart (only took 15mins this time), pulled out my new disk, and basically connected it to my PC in a external USB drive box. It worked fine. Ugh. Was terastation broken? I tried the old drive, that terastation thought was dead. It also seemed OK by PC standards. Ugh.

After going back in forth and trying different things, it turned out that the new drive had to have the jumper in Cable Select to work. The older 3 western digital drives were not in Cable Select mode. Whatever.

Also, the LED lights on the front don’t always do exactly what the manual or FAQ says. Specifically, i loved this blog on replacing terastation drive, but at the what he says is different than what i saw. Once I clicked ‘Restructure RAID Array’ , the lights were all going nuts and within a minute it went to a page that said “Restructuring has completed successfully” “Checking RAID Array”. At this point my 8 drive lights are blinking red and green – the 3 old ones have solid red status, new one is not lit, and all 4 have blinking green activitiy. Power light is on, diag light is blinking green. On web interface, i clicked on Raid Array 1 and it says it is “Rearing (x.x % Complete)”. I waited a few mins and refreshed page .. percent complete is increasing. It’s working !!! 4 hours later it finished – my setup is as good as it ever was.