We have seen where the mysql db will corrupt due to scans and scanning applications. When this happens the ArchMgr stays running. The Events view in Spectrum will not have any events but there is no error.
There is no indication that there is a problem unless you look at the MYSQL.OUT and/or ARCHMGR.OUT files.
When you look at the $SPECROOT/SS/DDM/ARCHMGR.OUT file you will see:
Failure executing query. - Table 'ddmdb.event' doesn't exist
The Archive Manager process was not shutting down when the mysql database corrupted.
This is tentatively scheduled to be fixed in the 25.4.6 release of NetOps. You will need to add the following entry to the $SPECROOT/SS/.vnmrc and stop and restart the SpectroSERVER for the changes to take effect:
SHUTDOWN_ARCHMGR_ON_MYSQL_DOWN=true