A Database issue on the primary hub caused the database to run out of space. After resolving this there were no data in Unified dashboards or metrics tabs in USM.
When checking the data_engine log there are multiple errors like
Nov 17 10:40:11:850 [139957146482432] de: data_engine [LSV] [LSV] - MySQL_BulkInsert::Commit - Error: [LSV] thread_id: 50255, error: MySQL_BulkInsert::Commit: Table 'ca_uim.t_qos_snapshot' doesn't exist (errno:1146)
The db space issue has caused a db corruption.