Failed drive replacement

Hi Everyone,

I had a drive fail over the weekend and wondering if what I experienced after is normal or not. It feels a little weird and I want to make sure that I’m safe.

I came home late Saturday night to find that one of my drives died. The bad drive was solid red with the rest blinking and I had messages about data not being protected.

Apparently the drobo rebuilt itself so that it it was only using 3 drives. When I woke up today, the 3 good drives were all green and dashboard was showing that my data is protected with a storage capacity of the 3 2 TB drives. I only have about 2.5 TB on the drobo, so everything fit on the smaller size. It was cool that the drobo rebuilt itself this way.

This afternoon the replacement drive that I ordered arrived. I popped it into the slot that housed the bad drive. My drobo didn’t respond to the drive. I was expecting it to go into rebuild mode right away like when I upgraded the drives last summer. The bay’s light stayed black and nothing happened.

I decided to try rebooting the drobo. I properly shut it down and then booted it back up. The boot took a bit longer than usual. Probably around 8 min. When the boot finished, all 4 bays had green lights and the dashboard showed capacity at 5.42 TB which is the correct size for all 4 drives.

A rebuild never happened after adding the new drive. Is this normal? I’m wondering if the rebuild that happened when it only had 3 drives took care of the rebuilding and it was able to simply append the new drive without needing another rebuild. It’s the first time I’ve experienced this.


that is perfectly normal. adding a drive doesnt involve a “rebuild”.

a rebuild is where it rebuilds missing data - if you have a “safe” drob and simply add a drive, then it is immediately available.

drobo WILL re-distribute/relayout the data, but because you are still fully protected the whole time it does this, all the lights remain solid green and it does this “silently” (i.e. without telling you). it continually optimises the data layout in the background anyway (its why it sometimes sounds like its doing something even when you are are not reading or writing to it.)

Thanks for the info. Fortunately this is the first drive I’ve had die on me in it, so it’s all new. I was expecting it to flash for a day or so like it did when I replaced 1 TB drives with 2 TB ones. Glad to hear that it’s normal.