2.9 The Archiving Options Category

Mailman comes with a built-in web-based archiver called Pipermail, although it can be configured to use external, third party archivers.

archive
This option tells Mailman whether to archive messages it receives or not, regardless of whether Pipermail or a third party archiver is used. Turn this off if you don't want to archive messages.

Note that senders can control whether their own posts are archived, on an individual per-message basis. If the posted message has a X-No-Archive: header (regardless of value), or a X-Archive: header with a value of No (case insensitive), then the message will not be archived, although it will be treated as normal in all other ways.

archive_private
Controls whether Pipermail archives are private or public. Private archives require a valid member address and password, or a list administrator password in order to access them. This option has no effect when a third party archiver is used.

archive_volume_frequency
Controls how Pipermail splits messages in the archive. The most common option is Monthly meaning a new archive volume is started every month. Very high volume lists may want a shorter frequency (e.g. Weekly or Daily) where as lower volume lists may want a longer frequency (e.g. Yearly). This option has no effect when a third party archiver is used.