Inodes in linux are assigned to files and are limited.
The Diagnose checks, if enough free Inodes are available, they are needed to create new files.
Following reasons could be the cause, if the appliance is running out of free inodes:

  • Mails in the Archiv Spooler are not processed (Storage Failure or Container Problem)
  • Mails in the MailQueue pile up (As a result of a spam attack or transport Errors of incoming mails to the mailserver)