Document DTABLE_SERVER_PING_TIMEOUT variable

docs/installation/faq.md

@@ -58,6 +58,23 @@ description: Troubleshooting tips for common SeaTable Server issues including st
 
     If the container is not (healthy), you can be sure, that something is wrong with the container.
 
+??? question "Check dtable-server"
+
+    You can check the status of `dtable-server` by executing the following curl request:
+
+    ```bash
+    curl https://$SEATABLE_SERVER_HOSTNAME/dtable-server/ping/
+    ```
+
+    If `dtable-server` does not reply, it might be stuck in a reboot loop.
+    This can happen if too many large bases are loaded at once or too many pending operations need to be replayed.
+    In this case, `monitor.log` contains log entries such as `[WARNING] Ping error, kill dtable-server`.
+
+    As a workaround, you can increase the timeout for the healthcheck request to give `dtable-server` more time to load bases and apply pending operations.
+    This can be achieved by increasing the value of the `DTABLE_SERVER_PING_TIMEOUT` environment variable (the default is `20`).
+
+    **Note:** This variable is not part of the default `seatable-server.yml` file, so you need to include an additional `.yml` file in order to configure this variable.
+
 ??? question "Check nginx"
 
     There might be a misconfiguration of `nginx.conf`. nginx provides a configuration checker.