Files dessapear on Drobo 5N

Hi i Have a Drobo 5N 30TB. I was using it for year ago. 10 iMacs and 2 PC with windows 7 use drobo as a storage by ethernet connection.

Today I see that the files we saved yesterday dissapear, only the folder is there . but after check all the files we see that a lot of files dessapear, some has more than a month ago.

I installed the latest firmware and dashboard update today, also connect to drobo using an SSh connection, in order to see the files but nothing is there. our information is very critic since we work for video broadcast and the files that we recorded with our cameras dissapear, we can’t recored again please help