i am new to HADR windows environment, here i see HADR primary as disconnected but some applications are able to access the primary,
how to make sure it is connected and HADR in active, can you please suggest.
HADR is the connection to the standby server. That is what is down. If people are connecting to the primary, then they should be fine. You need to look at the standby to see if there is an issue there.
You need to check in db2 diag logs to find out reason why HADR got disconnected. Its due to some error or someone stopped HADR intentionally due to any requirement.
Check HADR status ( stopped / running ) on both the servers ( Primary/Stand by) if it is stopped try to start HADR. Check diag log when you are trying to start HADR.
if log gap is high or you are unable to start HADR then take online back up of primary database and restore it on standby. No need to update parameters again. Try to start HADR again.