Drobo S failing but all LEDs green

My Drobo S (second gen) started being very slow yesterday, to the point that copying files to it using the Mac’s Finder and iTunes could not complete.
The latest Time Machines backup took over 2 hours for 6GB (to an identical Drobo S by the way), which is under 1MB/s.

However, all LEDs were green.
I power cycled it a few times, ensured that Drobo dashboard and firmware were up-to-date.

I suspect there is something wrong on the hardware side but I have no way to find out which disk is the culprit.
Trying to get an indication of that, I removed one drive for one second then put it back on.
NowThe Drobo S, after power cycling, now reports it is protecting data …and needs 335 hours for that (and going up!)

I am fed up with these Drobo drives and have ordered 2 4TB drives which I plan to use concatenated or with RAID 0 in FW enclosures (my Mac mini does not have USB 3 or Thunderbolt but is heavily modified for sound quality, so I will keep it even if its inputs and outputs are slow)
This is a risky setup but I still have a working Drobo with Time Machine backups, and it can’t be worse than my current Drobo setup.

Any help greatly appreciated.
Thanks in advance and have a great day.

hi, its good to hear that things are still working.
the rebuid will probably take 1day per 1tb of data that you have. (please let the drobo rebuild before trying other things, and probably best to not eject any more drives.)

for the slowness, one thing to bear in mind is that there could be several reasons for slowness, and while they may not necessarily apply in your case, here are a few examples:

  • itunes re-cataloguing your music libraries
  • finder spotlight indexing
  • time machine schedule (settings)
  • hard drive having a hiccup
  • antivirus schedule (or settings)
  • recent batch of files being deleted on drobo and free space blocks being reclaimed
  • drobo reshuffling large amount of new data (needing some time to settle)
  • multiple users or programs accessing/using the drobo at same time
  • free space running low on drobo

if you have any more info about your drobo such as which drives and sizes are in which slots, and how much data you have / free space, and if you are running in single or dual SDR/DDR drive redundancy mode, we can try to eliminate some possible causes.