</para>
<para>
- In contrast to read only
- backends like idmap_rid, it is an allocating backend:
- This means that it needs to allocate new user and group IDs
- to create new mappings as requests to yet unmapped users are answered.
+ In contrast to read only backends like idmap_rid, it is an allocating
+ backend: This means that it needs to allocate new user and group IDs in
+ order to create new mappings. The allocator can be provided by the
+ idmap_tdb2 backend itself or by any other allocating backend like
+ idmap_tdb or idmap_ldap. This is configured with the
+ parameter <parameter>idmap alloc backend</parameter>.
</para>
<para>