конфигурация backend для slapd (configuration backend to slapd)
OVERLAYS
An overlay is a piece of code that intercepts database operations
in order to extend or change them. Overlays are pushed onto a
stack over the database, and so they will execute in the reverse
of the order in which they were configured and the database
itself will receive control last of all.
Overlays must be configured as child entries of a specific
database. The entry's RDN must be of the form
olcOverlay={x}<overlaytype>
and the entry must have the
olcOverlayConfig objectClass. Normally the config engine
generates the "{x}" index in the RDN automatically, so it can be
omitted when initially loading these entries.
See the slapd.overlays(5) manual page for an overview of
available overlays.