Add note on domain metadata and backends

Closes #568

diff --git a/docs/markdown/authoritative/domainmetadata.md b/docs/markdown/authoritative/domainmetadata.md
index 5403fd3640be55294f8f5f1153e6a97d830bf02f..84e97d29b7db0a93fd5d6145b9a4a819e190033b 100644 (file)
--- a/docs/markdown/authoritative/domainmetadata.md
+++ b/docs/markdown/authoritative/domainmetadata.md
@@ -1,11 +1,17 @@
 # Per zone settings aka Domain Metadata
-Starting with the PowerDNS Authoritative Server 3.0, each served zone can have
-"metadata". Such metadata determines how this zone behaves in certain circumstances.
+Each served zone can have "metadata". Such metadata determines how this zone
+behaves in certain circumstances.
 
 **Warning**: Domain metadata is only available for DNSSEC capable backends! Make
 sure to enable the proper '-dnssec' setting to benefit, and to have performed
 the DNSSEC schema update.
 
+For the BIND backend, this information is either stored in the
+[`bind-dnssec-db`](backend-bind.md) or the hybrid database, depending on your
+settings.
+
+For the implementation in non-sql backends, please review your backend's documentation.
+
 ## ALLOW-AXFR-FROM
 Starting with the PowerDNS Authoritative Server 3.1, per-zone AXFR ACLs can be
 stored in the domainmetadata table.