Can anyone give me a rebuild estimate?

Hi all,

I have a Drobo with 4x1TB drives. I’ve removed the 1TB drive the drobo told me to remove and replaced it with a 2TB drive.

It’s currently saying 396 hours to rebuild and has done so for the last 3 days. It’s went up and down from as much 400 to 20 so I’m not sure what to expect.

I can’t put another 2TB drive into it until the first is settled in so was wondering what timeframes to expect?

Anyone have any ideas? Is this normal? I thought the whole beyond raid thing meant hours not days. Quoting the estimate in hours isn’t the same thing.

Try to reboot your system (while keeping the Drobo connected and powered on).
Check after the reboot if the time estimate in Drobo Dashboard remains the same.
When I did the same as you (4x1GT -> 3x1TB + 1x2TB) on my Drobo 2G, it took a little less than 3 days, so you seem to already be above average.
But if you have regular I/O activity on your Drobo at the same time as it rebuilds, then the lengthening is normal.
And remember you will have to endure this a second time, since you need 2x2TB to get any usable size increase…
And yes, this fine point is not really advertised in DRI marketing brochures…

Restarted computer, it has now settled at around 33 hours (with a few jumps up to around 160/190). Sometimes I can hear some I/O activity but for the most part I cannot hear very much, a few clicks every 10 seconds or so. I’m not accessing any data (unless the computer is doing something every so often). The drives don’t appear to have spun down though.

How can I know if it’s actually doing what it’s supposed to? Does the timer only actually move if the Drobo is doing things or is it just a software trick? How often is Drobo Dashboard polling the Drobo for an update?

Thanks for your help.[hr]
Had to restart the computer again anyway, now at 141 hours, the progress meter has reset.

I really hope it’s just very inaccurate at guessing the time needed and the Drobo is actually doing what it said it’s been this last while.

it should take less than 48 hours, probably closer to 36

ANYTHING accessing the drive (be it windows search/google desktop search/OS X finder) will DRAMATICALLY slow it down.

if you dont need to use your drobo… the fastest way to do it would be

  1. turn off your computer
  2. unplug the USB cable (drobo will stay on and will continue to rebuild)
  3. restart and use your computer as normal (without drobo attached)

that way nothing will be accessing drobo and slowing it down and it will rebuild at the fastest rate possible. As soon as drobo has finished rebuilding it will go into standby (thats how you know its finished)

Will restarting/shutting down the computer affect anything? It doesn’t restart the rebuild process at all?


no, otherwise i wouldnt have advised you to do it :stuck_out_tongue:

drobo will just carry on rebuilding regardless - but by having it disconnected you can be sure that nothing on your computer will be slowing it down

the only thing i know of which can re-start the rebuild is to pull diagnostics off drobo

Also how full were you? If you were close to very full it will take longer, longer than the normal 36 to 48 hours.