Have two Drobo 5N’s one with 5 8TB drives and the other with 4 5TB drives and 1 6TB. I am upgrading capacity by replacing 3 of the 8 TB drives with 10 TB drives. Want to use the removed 8TB drives in the second 5N replacing 3 of the 5TB drives. Upon replacing the first 5 TB drive with the removed 8TB from the other Drobo, get error that drives for two different drobos are installed, with critical red light indication stating to remove drive. Tried erasing and reformatting the drive 3 different ways on my iMac and a Basic erase and reformat on my Win 7 PC and still no go. So, am I to assume that once you use a drive in one drobo you can never use it in another, even when the drive is larger to increase capacity. The drive must be brand new? (Single Redundancy exchanging one drive at a time, with units powered off then back on)
Try removing the existing partition on the removed/wiped 8TB drive, and then allow the Drobo 5N2 to create its own partition on that drive.
I found it was necessary to completely wipe the disk (filling it with hex 0’s). To do this, take the drive over to a Linux or mac system and locate the drive name with “lshw -short” on Linux or “sudo diskutil list” on Mac. Once you are certain you have the right drive to erase, run “sudo dd if=/dev/zero of=/dev/the_device_name_you_found bs=1048576” to overwrite the entire disk. BTW, if the mac reports your drive is “disk94”, use “/dev/rdisk94” to bypass the cache subsystem and write to the raw disk. Depending on how you have it connected - don’t use USB 2.0 - it may take an hour or two per terabyte to erase.