Drive failure and replacement

I have a DroboPro with two 1TB WD Caviar green drives in it that are a little over a year old. Turned the unit on this morning and was surprised to see a drive failure warning appear and blinking red light on one of the drives. I replaced the drive with another 1TB WD Caviar blue drive and was pleased to have the rebuild seamlessly complete after a little under 4 hrs - while with my data still intact and working - thanks DataRobotics!

I then added a third drive, another WD Caviar 1TB blue drive and choose the dual redundancy option to further protect my data. That reallocation also went smoothly - thanks again DataRobotics!!

I was curious about the drive that went bad and decided to shutdown, pull all my working drives and to insert just the one ‘bad’ drive. To my surprise, the entire system booted fine with all my data intact on just this single drive! I did get a warning that the drive was in imminent failure mode though.

Next step was to put the 3 working drives back in, boot up, and then when the DroboPro was mounted to re-insert the supposedly ‘bad’ drive. It came up flashing red signalling that it needed to be removed. My question is, is there any way to reformat or test this drive using the Drobo Dashboard or Advanced tools to see if there is actually any damaged or to reformat and remap bad blocks or do I have to go with a third party utility for that? It would be nice to have an option to insert a disk and work independently with it in a given slot on the DroboPro. I’m connected directly to my computer using FW800 port.

Is there any way to verify the disk and add it back into my disk array with some confidence that it is not going to fail?

generally drobo is very “cautious”

disks it fails may go on to work ok in desktops and stuff, but it has failed them for a reason, something is starting to “go”

if you want to know what take a diagnostic log and send it to DRI and they will tell you why drobo failed a disk

Drobo’s look at a few factors for failing a drive. Bad blocks/sectors. Time Outs and Disk Start Errors. When it reaches a certain threshold in a certain amount of time then it flags that drive as failed. This threshold is generally a little more cautious then computers or diagnostic tools. But they are physical issues of the drive and I would not trust that drive after the Drobo has flagged it as failed.

Also, once the Drobo has flagged that drive as failed, it records the serial number of the drive and will always see that drive as failed.

Thank you, Jennifer, for the clear explanation. I just have a 2TB WD drive that was marked “failed” by my DroboPro. That drive was purchased at BestBuy only a little over a month ago. Even though I had doubts on the Drobo at that moment, I still took it back to BestBuy and was lucky enough to get it exchanged. Now I understand that I’ve done the right thing for the sake of my data.

And I also like the fact that Drobo will record failed drive serial numbers. That sounds very helpful when the user is confused by a bunch of similar looking drives.

Keep up the good work DR!