doc/operation: add a note about backup/restore of generated catalog zone unique-id's

diff --git a/doc/operation.rst b/doc/operation.rst
index 29132efad586cde6b88e7330e91f5439bc4a8787..0c20f6a1527d75af327094514571fcf28211ef96 100644 (file)
--- a/doc/operation.rst
+++ b/doc/operation.rst
@@ -1562,6 +1562,11 @@ The restore procedure does not care for keys deleted after taking the snapshot.
 Thus, after restore, there might remain some redundant ``.pem`` files
 of obsolete signing keys.
 
+.. NOTE::
+   Automatically generated unique-id's of member zones are kept in the
+   timers database. Therefore, backup of member zones' timers is crucial for
+   backup/restore of a :ref:`generated catalog zone<catalog-zones>`.
+
 .. TIP::
    In order to seamlessly deploy a restored backup of KASP DB with respect to
    a possibly ongoing DNSSEC key rollover, it's recommended to set