Can I make this swap?


Gen 3 Drobo (Media)
Bay 1 - 3TB (WD Red, new)
Bay 2 - 3TB (WD Red, new)

Gen 2 Drobo (backup of media)
Bay 1 - 2TB (WD Green, older)
Bay 2 - 2TB (WD Green, older)

Firmware and Dashboard all up to date

The Gen2 drobo is practically full, the drives are older and I think have been rewritten once or twice when it migrated from being my media drive to the backup. I’m a little nervous as last week both drives in the Gen2 flashed red. I don’t know how long that occurred but it did stop and I got the notification that all is fine, though I haven’t run a backup since.

Since I’d like both Drobos to match capacity, I bought 2 more 3TB WD Red drives. It should work like this, right?

  1. Put both new 3TB drives in Drobo 2
  2. Allow Dashboard to do it’s magic and populate the drives
  3. Take out 1 - 2TB drive and put in Drobo 3

Final setup would look something like this:

Gen 3 Drobo (Media)
Bay 1 - 3TB (WD Red, new)
Bay 2 - 3TB (WD Red, new)
Bay 3 - 2TB (WD Green, older)

Gen 2 Drobo (backup of media)
Bay 1 - empty
Bay 2 - 2TB (WD Green, older)
Bay 3 - 3TB (WD Red, new)
Bay 4 - 3TB (WD Red, new)

And then if I’m OCD, I could take the drive out of Bay 4 and put in Bay 1?

I just want to make sure it’ll all work before doing anything stupid.

What you suggest should work, however if you have suspicions about the 2TB drives you may want to reconsider your plan. Doing the rebuilds will put a lot of stress on your drives (1 day of solid use per TB stored for a rebuild on a Gen 2 is common). If your drives are flaky it might be better to just retire them, or to do a full surface scan before you put them back into a Drobo.

The best plan is probably this:
A) Do a full backup of Drobo #1 to Drobo #2.
B) Shut down Drobo #2
C) Pull out BOTH 2TB disks from Drobo# 2 and set them aside. You can put this disk pack back in if disaster strikes during any of the following steps, just make sure to do it with the power OFF and have ONLY the two 2TB disks in the Drobo.
D) Put both the new 3TB disks in Drobo #2, and set it up from scratch with the volume sizes and formats you want.
E) Do another backup from Drobo 3 to the “new” Drobo #2.
At this point you have two matching Drobos with 2x3TB in each. If you want to re-use the 2TB disks I’d find something to do deep surface scans, etc. and make sure they’re 100% before reusing. If they check out then:
F) Put 1x2TB in each Drobo, probably waiting for rebuild before doing the other one.

If you want to go ahead with your original plan, here’s what I would do:

  1. Add one 3TB to Drobo #2 with power ON. Wait for the rebuild.

  2. Add the second 3TB to Drobo #2 with power ON. Again, wait for the rebuild.

  3. Wait for all green lights, then with power ON pull one 2TB drive from Drobo #2.
    I’d probably wait for the rebuild of Drobo #2 at this point before moving on, but that’s up to you.

  4. With the power ON insert the 2TB drive into Drobo #1. Wait for the rebuild.

You’re basically done at this point. If you want to get the arrangement of the drives right (I probably would too) then
5) Put the Drobo into standby from Dashboard
6) Pull the plug
7) With the power OFF rearrange the drives
8) Power back up and reconnect when you’re happy. There should be no rebuild at this point, it just recognizes that the disks have shuffled and gets on with it’s job.

Sorry this ended up a bit long, but hopefully it makes sense.

Thanks for the reply.

I like your plan of just taking out the 2TB drives, having a full backup so they’re the same, and then adding back in the 2TB drives.

Only thing I don’t know how to do is the deep surface scans. I probably need an additional hardware dongle. I might have a USB thing, but I don’t know if it’s just for 2.5" drives or if it’ll fit these drives.

It’s hard to say if the drives might be starting to fail. Like I said, they both blinked Red, but it wasn’t very long. There were several rebuilds that happened since it became a backup drive (and I added about 1TB of data), but only went red once briefly. I haven’t backed up to it since, but it’s mounted fine and been green.

hi dave,
for the drive tests, if you are on windows the wd tool mentioned here is quite good:
(it has been able to run on wd drives as well as other makes but if yours are wd it should run a treat)

(just to reinforce what spiney mentioned, i would also wait for one drobo to fully finish and return itself to a working state, before working on the other)

after step C) i think it was implied that the drobo would then be powered up empty, before starting step D)?

I probably should’ve mentioned I’m on a Mac.

Found a couple of references that say to just use Disk Utility to reformat the drive and erase free space to zero. If you can figure out how to do that in the disaster area that is Disk Utility on El Capitan please let me know…

hi spiney, i seem to remember something about some disk utility features changing or being made part of another cocktail tool that comes with the mac… maybe that part of mac has the features you were mentioning?

btw dave i also had a look but while i could not see the same lifeguard tool, they do seem to have similar tools for mac which can be found here in their downloads section:

Currently backing up New drobo to “new” old drobo, now that both are 2X3TB. I don’t have a 3.5" SATA to USB cable, only a 2.5", so I believe I’m missing the power. I ordered a cheap one from Amazon and should arrive next week. But since I don’t need those 2X2TB drives, I can continue to use and enjoy my now mirrored Drobos. I’ll report back if I figure out what Disk Utility can do. I used to use it here and there, but they made big changes in El Cap, and I haven’t needed to dig in for a while.

startech make some good adapters (i got an ide to sata and i think the other way around too), but for usb, icydock have one that allows for ide, 3.5, 2.5 and sata, through to usb, (though the 1st one i got had a broken power switch, and the 2nd one works great but the power switch seems too wobbly for its own good) :slight_smile:

Got my $13 dingle. Used it for a couple minutes on each drive and it’ll get packed away for a while.

Using disk utility in El Cap, I ran first aid, formatted the drives, and ran first aid again. Seems to be no issues. Popped one drive into the backup drobo. Whatever rebuild it’s supposed to do took no time at all, went green right away. Will add other one as soon as the media drobo isn’t in use, just in case.

Thanks again for the guidance.

(“just in case” is usually good to consider) :slight_smile:
i wonder if anyone knows a person called justin case too :smiley: