PMDF System Manager's Guide

Chapter 32 has a general discussion of tuning PMDF performance. This section is to point out in particular two of the issues discussed therein.

Perhaps even more than on a general PMDF system, you can want to consider using the queue channel keyword to segregate different channels' message processing to different queues, to ensure that particularly heavy traffic over one channel will not impact message traffic over another channel; e.g., you can want to have one queue dedicated to your tcp_local channel and a different queue dedicated to your tcp_internal channel.

If the e-mail firewall system is not a system logged into regularly and thus subject to longer than usual spells where no one is actively checking it, thus potentially large buildups of backed up messages, then use of the subdirs channel keyword to split message files among multiple subdirectories can be a particularly good idea, to postpone the time at which OpenVMS RMS or UNIX directory performance begins to suffer due to large numbers of files in a single directory.