Drobo 5C annoying hum

I’ve had a Drobo 5C for about 4 months, and for a while now its been making an annoying hum. Its clearly vibration related, if I touch it it stops. I powered it down and used compressed air and a shop vac to clear dust out of it. That helped some but not completely.

I suspect its the fan, a transformer or one or more drives. I know I probably can’t remove all the drives to rule out the drives, but I believe I can pull one drive out and operate it in degraded mode. BTW, I have it set up for 4 drives with dual disk redundancy. I believe if I pull one out, it has to go through a rebuild, but that’s not a problem it just takes awhile. Is that correct? If so I can pull one at a time, run it for a while, and do the next drive and so on. That would allow me to identify a noisy drive. It wouldn’t let me identify two bad drives, but that hopefully is only a remote possibility.

Question, assuming that will work, should I shut down, remove the drive, and restart. Or can I pull it out hot.

I have the same issue, it is one or more of the drives vibrating against a metal surface in the unit. You can try reseating the drives but mine when back to buzzing. Didn’t use to do this.

I ended up calling Drobo support, the tech asked to send a file, and they were able to determine which drive was having issues.