gen2 loop restart after expanding volume

I have drobo gen2 connected to mac mini via FW800. I have been using it successfully with 4x 2TB Hitachi drives. I have upgraded my 16TB volume to 3x 3TB HGST drives, but when I added 4th one the problem started.

drobo is doing expansion of volume size (orange/green blinking) but after a while (about an hour or two hours) all LEDS are going RED, and then the drobo restarts. Expanding starts again (it is continued, as I see in drobo desktop app as time to finish is getting lower). and so on, and so on.

What is wrong?

Can someone help with this?

All HGST HDD’s were checked in linux and were all OK.

best regards,

hi prregor, sorry to hear of your problem,
it sounds as though 1 or more drives encountered some problems during the expansion process and that could account for the reboot loop (or rebuild loop)

if dashboard can still see the drobo, and if it does show you an estimated time remaining which is getting lower, it might be worth letting it take place a bit more, though how much time is it showing remaing?

it shouldnt just keep rebooting the unit over and over, though can i also check about those hard drives… for example when you mention they were checked in linux, and that they were ok, was this in the past, (or have you actually powered down and taken the drives out and retested them since having this issue?)

while it is looking like a rebuild, i would be inclined to let it run through the rebuild process with flashing yellow and green lights (or orange/amber/yellow and green) at least for as long as 1 pass of rebuild would take… which is usually about 1day per 1TB of data that you have on it plus a bit)… though if it is the reboot loop issue, then one thing you could try later would be to try putting the drobo into a read only mode, which could help to stabalise things to hopefully be able to at least access your data to copy off somewhere, for example as mentioned here:

Thanks for answer Paul.
I have taken drobo apart, cleaned it, put some small aluminum radiators on motherboard, replaced fan with Noctua 1600RPM, removed honeycomb with dremel both from steel construction and from back plastic part.

It took 3 days to rebuild matrix. All LEDs are green.

However… I do have another problem. The MacOS is not allowing me to write anything to drobo. When I start up my mac mini (El Capitan), I do have an system error:

“MacOS cant repair the disk ‘drobo’.”

it looks like this:

I do not know how to fix this. Is there any other way then copying all files from drobo to external disk, recreating volume and copying data back to drobo?

It would take me week to do this. :frowning:

hi, would you be able to try shutting all down and then after about 5 minutes, to try connecting it via usb direct cable instead?

i think something similar has happened before and a usb fixed it and might be worth a try when you can?