OS X 10.12 (Sierra) and Gen 3 low space/can't write issues

Since upgrading to OS X 10.12 (Sierra), my Gen 3 array has been having issues; namely:


  • 990GB used on actual 2.1TB available (16TB volume)
  • the only consistent writing to the volume is Crashplan
  • all 4 drives report as “good” (2 x 1TB, 2 x 750GB)

getting a regular warning nightly of:

[align=center]Red Alert. Drobo is critically low on capacity. Please add or replace a disk to increase capacity or you will experience an impact in performance.[/align]

After that warning, the volume becomes read-only with Finder spitting back an error of:

[align=center]The operation can’t be completed.
An unexpected error occurred (error code -50)

and the only way to resume normal operation is to reboot.

Any idea what might be happening?

hi jeff, are you able to see what is running at night, to cause that message?

for example, is it a crashplan routine that is scheduled to run each night, or is theere possibly something else like another program, or a time machine backup that is trying to run?[hr]
(am just linking to your other related post too)