Drobo

Dual disk redundancy?

My current setup is 2x2TB and 2x1.5TB with dual-disk redundancy turned on, for a total of 2.7TB of usable space. I was curious to see what status a single dead drive would leave the drobo in, so I pulled one of the drives. The remaining three drives immediately started flashing yellow/green and I got a notice from the drobo dashboard saying “Drobo cannot currently protect your data against hard drive failures”. Shouldn’t dual-disk redundancy mean I don’t get that message until two drives are removed/failed?

Once my data is backed up somewhere else (hopefully soon) I’ll try again but remove two drives, maybe the dashboard is just being overly cautious with the messages it’s giving me?

hi, i “think” its warning you that it cant protect against any “more” drive failures for some reason.
are you able to confiorm which drive did you pull out?
and how much was your existing data using?

flashing yellow and green should indicate its doing a re-layout to get things better protected again (im not sure if the initial re-layout needs to take place, before youre protected against a 2nd drive, but maybe someone can confirm that)[hr]
also - make sure you have backups before forcing the unit to “test” things like removing drives etc… its robust for sure, but be careful

you have 2 disk set, so it’s saying it can’t protect you like you want.
It’s in the process of laying itself back out so that you can have dual disk again. while it’s doing that there is a chance you could run into problems.

if you were to pull another disk, you would be left with 2, which means they would both be data protection and not data. although you should still be able to access your data, it would not be very happy until you started to put disks back in.

I’m using 1.3TB of space, just under half of the available storage. I pulled out the topmost drive, but that really shouldn’t matter. I can’t control which drive fails if one of them chooses to.

That’s what I expected, but I’d feel much more confident if the dashboard said something different like “Your data will only survive 1 more hard drive failure in its current state” instead of giving me warnings of doom :-/.

I forgot where, but this was mentioned in another thread.
You do get the same warning from Drobo Dashboard on 1st drive loss and 2nd drive loss with DDR enabled.

Essentially it’s “Drobo can no longer protect your data from failures at the level of protection you have specified

I think to some degree it’s to prevent people from getting overzealous and saying “Hey, I have DDR, I’ll upgrade two disks at a time” because the relayout process is disk-intensive and can possibly expose weaknesses in the remaining drives, which could result in complete data loss in a DDR-minus-two-drives scenario.

Be afraid… BE VERY AFRAID! :wink: