The db2 connections take between 9 and 30 seconds.
The vasd on the server is using up to 50% of the CPU ability.
The issue has become more noticeable as connection requests have increased.
Many connection requests per second from the same account.
See what is showing for db2set.
(/opt/udb/home/pdbin170) 132: db2set
In this particular case adding the following resolved the issue:
Use the DB2_NUM_CKPW_DAEMONS registry variable to start a configurable number of check password daemons. The daemons are created during db2start and handle check password requests when the default IBMOSauthserver security plugin is in use. Increasing the setting for DB2_NUM_CKPW_DAEMONS can decrease the time required to establish a database connection, but this is only effective in scenarios where many connections are being made simultaneously and where authentication is expensive.