On Tue, Aug 28, 2012 at 11:48:19AM -0500, Stan Hoeppner wrote: > So maybe for this particular application a ramdisk isn't a horrible > idea. But he still has the problem of implementing parallel submission > in his java application, otherwise it won't matter if it's a ramdisk or > an old 3600 RPM MFM drive on an 8 bit controller.
It should be noted that parallel submission is not a work-around for Postfix per-client rate limits (the default in_flow_delay is a rather soft barrier in any case). Rather, parallel submission is a way to ammortize SMTP latency across multiple connections. In the same time that it takes to process a single incoming message, it is possible to accept multiple parallel messages. For clients with a low-latency (LAN or campus network) connection to the SMTP server, concurrency of ~20 connections is often sufficient to saturate the server's disk bandwidth (or CPU bandwidth if moderately expensive content filtering is in place). Strictly serialized SMTP submission is slow because it fails to fully utilize idle CPU, network and disk cycles. -- Viktor.