DBCLNP chore

docs/PERFORMANCE.md

@@ -0,0 +1,24 @@
+# Performance tips
+
+The application runs regular maintenance a DB cleanup tasks. If these tasks fail, you might encounter performance issues. 
+
+Most performance issues are caused by a big database or large log files. Enabling unnecessary plugins will also lead to performance degradation. 
+
+You can always check the size of your database and database tables under the Maintenance page. 
+
+![Db size check](/docs/img/PERFORMANCE/db_size_check.png)
+
+> [!NOTE]
+> For around 100 devices the database should be approximately `50MB` and none of the entries (rows) should exceed the value of `10 000` on a healthy system. 
+
+## Maintenance plugins
+
+There are 2 plugins responsible for maintaining the overal health of the application. One is responsible for the database cleanup and one for other tasks, such as log cleanup. 
+
+### DB Cleanup (DBCLNP)
+
+The database cleanup plugin. Check details and related setting in the [DB Cleanup plugin docs](/front/plugins/db_cleanup/README.md). Make sure the plugin is not failing by checking the logs. Try changing the schedule `DBCLNP_RUN_SCHD` and the timeout `DBCLNP_RUN_TIMEOUT` (increase) if the plugin is failing to execute.
+
+### Maintenance (MAINT)
+
+The maintenance plugin. Check details and related setting in the [Maintenance plugin docs](/front/plugins/maintenance/README.md). Make sure the plugin is not failing by checking the logs. Try changing the schedule `MAINT_RUN_SCHD` and the timeout `MAINT_RUN_TIMEOUT` (increase) if the plugin is failing to execute.