SummaryThe TCPAD process in the Exinda can spike to 100% use of CPU when it is turned on to try and accelerate connections, regardless if there are any accelerated connections happening or not.
OverviewTCPAd - the process in the Exinda firmware that is responsible for managing TCP Acceleration - has been found in certain scenarios to utilize 100% of the CPU in the appliance, causing sluggish response in not only the UI, but in the processing of traffic for both monitoring and optimization purposes. This 100% utilization could happen regardless of the fact whether there were accelerated connections at the point of time or not; in fact, it can be seen when TCP Acceleration was just turned on: within a matter of moments, utilization will spike to be full.
CauseIt was found that in cases where a firewall was topographically in front of the Exinda, if it was blocking the first packet (the SYNACK) of an accelerated TCP connection. When a connection was attempted to be started, TCPAd would utilize all the CPU trying to initiate the connection, though it would never go through.
WorkaroundThere is no workaround for version v7.0.3u1 and lower of the Exinda firmware.
ResolutionThis problem has been fixed in v7.4 of the Exinda firmware; to resolve, please upgrade the firmware to v7.4.