>The client concurrency must not exceed the service concurrency, and >virus scanning is CPU intensive, and in my experience this is too much. > >Of course in a multi-filter chain, if any of the filters are high >latency, the combined filter latency can throttle the CPU demand >of any CPU intensive stage, and in that case, higher concurrency >may be appropriate, but if filters in a chain have vastly different >characteristics (impedance mismatch), it may be appropriate to >insert a Postfix queue in between: > > > Postfix -> filter1 -> Postfix -> filter2 -> Postfix ... > >Each Postix stage (except the last) sets a suitable content filter, has >appropriate concurrency settings, ...
I will update to the last Kaspersky AntiSpam, lower and do some changes so that client concurrency does not exceed service concurrency. If the problem remains, I'll try the chain you suggest and maybe move the Antivirus to another box.