Glassfish Memory Diagnostics

Hi,

This is with reference to issue which I'm facing on Glassfish. I have two Glassfish instance having same configuration (Memory and GC) but I have observed absurd behaviour on one of the instance.
Instance 1: On this instance GC working properly like when used memory reaches 2GB GC gets triggered and used memory gets released (500MB) it starts rising exponentially after 15 mins when used memory breached 2GB again GC gets triggered which is normal behaviour.
Instance 2: On this instance I have observed some absurd behaviour like on this instance we have continuous GC calls after GC triggered Used memory is released (500MB) then again within minute duration Used memory reaches 2GB as here Used memory released and abruptly gets raised which causes continuous GC calls because of which I’m getting suspension in PurePaths response time.
To trace issue I had trending Snapshot on instance which I’m facing issue which is not helping me to identify objects or classes consuming heap as whenever I have scheduled trending snapshot for trending GC gets called in between because of which used memory drops so I’m not able to identify objects.
Both instance having same configuration and versions also load is equally distributed over two instance.

Please find the attachment for better understanding.