## <a id="schemas"></a> Schemas
+### <a id="schema-status-files"></a> Status Files
+
+Status files used by Icinga 1.x Classic UI: `status.dat`, `objects.cache`.
+
+Icinga 2 specific extensions:
+
+* host and service objects support 'check_source' (added in Classic UI 1.10.0)
+* command objects support custom variables (added in Classic UI 1.11.2)
+* host and service objects support 'is_reachable' (added in Classic UI 1.11.3)
+
### <a id="schema-db-ido"></a> DB IDO
There is a detailed documentation for the Icinga IDOUtils 1.x
servicestatus | check_source | TEXT | NULL | node name where check was executed
hoststatus | check_source | TEXT | NULL | node name where check was executed
statehistory | check_source | TEXT | NULL | node name where check was executed
+ servicestatus | is_reachable | integer | NULL | object reachability
+ hoststatus | is_reachable | integer | NULL | object reachability
logentries | object_id | bigint | NULL | FK: objects table (service associated with column)
+ {host,service}group | notes | TEXT | NULL | -
+ {host,service}group | notes_url | TEXT | NULL | -
+ {host,service}group | action_url | TEXT | NULL | -
Additional command custom variables populated from 'vars' dictionary.
Additional global custom variables populated from 'Vars' constant (object_id is NULL).