I've run into this same scenario. We don't use a "sideband" CM platform for tracking host metadata and thus some of our host-specific parameter values stored in the Foreman DB are rather large.

I was not able to conveniently locate an "admin-facing" tunable which could either turn auditing off or otherwise "filter" what gets audited.

Coincidentally, we resorted to changing the "audited_changes" column type to MEDIUMTEXT as a testing workaround. My concern is that this approach is not quite "future proof" (easily superceded by an upstream rails DB migration). Are there notable objections to making MEDIUMTEXT the new default? Given that there appears to be no fulltext index on this column, Foreman system owners would just need to ensure sufficient filesystem storage.