Hello stress tests indicate that Postfix 2.8.8 behaves differently when using "postqueue -i" compared to "postqueue -f" when it comes to handling deferred e-mail.
When using "postqueue -i" in a loop, deferred e-mail goes through the incoming queue before going through the active queue. When using "postqueue -f", deferred e-mail goes directly to the active queue (so without going through the incoming queue). My question is: why is that? Also: the Architecture Overview (http://www.postfix.org/OVERVIEW.html) has a "How Postfix delivers mail" section where the deferred to incoming observation isn't shown (there's no arrow from deferred to incoming) so why does our test show that? Context: Our HDDs are suffering under heavy load. Each CPU core is in 40+% iowait with 1 CPU core being at 90+% iowait all the time. We believe that the qmgr process is responsible for the 90+% iowait CPU core so we're trying to improve performance in any way we can. Thanks for reading. Andrew
