docs: add 'no data' troubleshooting guide

performancecopilot · Jul 15, 2021 · 8e36676 · 8e36676
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diff --git a/docs/refs.rst b/docs/refs.rst
@@ -1,3 +1,4 @@
+.. _pmlogger: https://man7.org/linux/man-pages/man1/pmlogger.1.html
 .. _pmproxy: https://man7.org/linux/man-pages/man1/pmproxy.1.html
 .. _pmseries: https://man7.org/linux/man-pages/man1/pmseries.1.html
 .. _pmwebapi: https://man7.org/linux/man-pages/man3/pmwebapi.3.html

diff --git a/docs/troubleshooting.rst b/docs/troubleshooting.rst
@@ -1,11 +1,30 @@
 Troubleshooting
 ===============
 
+.. include:: refs.rst
+
 Common Problems
 ---------------
 
-**When I try to add a datasource in Grafana, I get:**
+HTTP Error 502: Bad Gateway, please check the datasource and pmproxy settings
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+**When I try to add a datasource in Grafana, I get the following error:**
 **"HTTP Error 502: Bad Gateway, please check the datasource and pmproxy settings. To use this data source, please configure the URL in the query editor."**
 
-- check if pmproxy is running: ``systemctl status pmproxy``
-- make sure that pmproxy was built with time-series (libuv) support enabled. You can find out if so in *$PCP_LOG_DIR/pmproxy/pmproxy.log*
+* check if pmproxy is running: ``systemctl status pmproxy``
+* make sure that pmproxy was built with time-series (libuv) support enabled. You can verify that by reading the logfile in ``/var/log/pcp/pmproxy/pmproxy.log``
+
+
+PCP Redis
+---------
+
+Grafana doesn't show any data
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+* Make sure that `pmlogger`_ is up and running, and writing archives to the disk (``/var/log/pcp/pmlogger/<host>/*``)
+* Verify that `pmproxy`_ is running, time series support is enabled and a connection to Redis is established: check the logfile at ``/var/log/pcp/pmproxy/pmproxy.log`` and make sure that it contains the following text: ``Info: Redis slots, command keys, schema version setup``
+* Check if the Redis database contains any keys: ``redis-cli dbsize``
+* Check if any PCP metrics are in the Redis database: ``pmseries disk.dev.read``
+* Check if PCP metric values are in the Redis database: ``pmseries 'disk.dev.read[count:10]'``
+* Check the Grafana logs: ``journalctl -e -u grafana-server``