The ProxySG may report the following in the event log:
2009-06-29 02:16:15-00:00UTC "TCP acceptance regulation: memory pressure is on" 0 30204:1 ../main/event_logger.cpp:36
In addition, the ProxySG may report memory pressure percentage in the Management Console.
Memory pressure simply is the percentage of physical memory less free and reclaimable memory, of total memory. If there is no free or reclaimable memory in the system, memory pressure is 100%.
It is tracked on the ProxySG Management Console, in Statistics > Device, in the Summary section.
The statistic that tracks memory pressure is called TM002.00.1.
The event logs start reporting memory pressure when it reaches 70%.
End users may notice "slowness" when viewing web pages when memory pressure goes above 70% and the ProxySG will go into "regulation" when memory pressure exceeds 80%. Regulation means that the ProxySG will no longer accept new connections until it can finish processing current requests and free resources. When a ProxySG goes into regulation, all users utilizing that proxy may experience extreme slow Internet access, or may not get any response at all, until the regulation is cleared.
Upon reaching the TCP regulation state the proxy physically shuts down incoming TCP connections, to alleviate the memory state that is occurring. By stopping new traffic coming to the ProxySG, it has time to deal with what is currently in memory. Hopefully memory use will then be reduced. When we hit the lower limit, in this case 75%, the ProxySG begins accepting new connections again.
If a ProxySG goes into regulation frequently, or experiences high memory pressure (above 70%) frequently, the unit may be undersized or there may be a memory leak. Please open a case with support for investigation.