Thanks Hoolio, those kicked loose enough mental debris that I was able to address the behavior. Essentially the problem originated with the idle timeout setting on a FastL4 profile associated with a Wildcard virtual server--set by default to 5 minutes. If I increase that setting to 10 minutes, then the database connection problem goes away, as the idle timeout on the F5 side is now longer than that of the database servers themselves. Here's the entry from the bigip.conf for the new FastL4 profile, should anyone be interested;
profile fastL4 fastl4HiTimeout {
defaults from fastL4
reset on timeout enable
reassemble fragments disable
idle timeout 600
tcp handshake timeout 5
tcp close timeout 5
mss override 0
pva acceleration full
tcp timestamp preserve
tcp wscale preserve
tcp generate isn disable
tcp strip sack disable
ip tos to client pass
ip tos to server pass
link qos to client pass
link qos to server pass
rtt from client disable
rtt from server disable
loose initiation disable
loose close disable
software syncookie disable
}
Nimbostratus