Customers attempt to update their public folder data usage with the "Update Size" button in Hosting Control Panel in POA, but the public folders is not changed and in CP message "Warning Update of public folder size was requested but not completed yet." is shown.
Public Folder in question in not yet processed by accounting task. Each time customer press 'Update size' button in CCP, POA marks respectively Exchange entity (mailbox or public folder) as ready for diskusage accounting and schedules task like 'Collect diskspace usage for service #471'.
Such tasks are limited by number of objects (mailboxes or public folder) to be served - default limit is set to 80. So task update usage only for 80 public folders at the time. The issue is that host can has more than 4.500 public folders, that are ready for accounting. As a result single task doesn't process it all.
This setting you may find in Top > Deployment Director > Server Manager > Hardware Nodes >
<SERVER_NAME> > Applications > Exchange2010Mailstore > Storage Usage Accounting:
Maximum number of public folders to update simultaneously
Increase limit for 'Maximum number of public folders to update simultaneously' to reasonable value, e.g. approximately 20% of the public folders stored on the server. This will increase time for task to be processed, but will update more public folders at once.