.. _users-guide-statistics: Statistics ---------- Varnish comes with a couple of nifty and very useful statistics generating tools that generates statistics in real time by constantly updating and presenting a specific dataset by aggregating and analyzing logdata from the shared memory logs. .. XXX:Heavy rewrite above. benc varnishtop ~~~~~~~~~~ The `varnishtop` utility reads the shared memory logs and presents a continuously updated list of the most commonly occurring log entries. With suitable filtering using the -I, -i, -X and -x options, it can be used to display a ranking of requested documents, clients, user agents, or any other information which is recorded in the log. ``varnishtop -i ReqURL`` will show you what URLs are being asked for by the client. ``varnishtop -i BereqURL`` will show you what your backend is being asked the most. ``varnishtop -I ReqHeader:Accept-Encoding`` will show the most popular Accept-Encoding header the client are sending you. For more information please see :ref:`ref-varnishtop`. varnishhist ~~~~~~~~~~~ The `varnishhist` utility reads `varnishd(1)` shared memory logs and presents a continuously updated histogram showing the distribution of the last N requests by their processing. .. XXX:1? benc The value of N and the vertical scale are displayed in the top left corner. The horizontal scale is logarithmic. Hits are marked with a pipe character ("|"), and misses are marked with a hash character ("#"). For more information please see :ref:`ref-varnishhist`. varnishstat ~~~~~~~~~~~ Varnish has lots of counters. We count misses, hits, information about the storage, threads created, deleted objects. Just about everything. `varnishstat` will dump these counters. This is useful when tuning Varnish. There are programs that can poll `varnishstat` regularly and make nice graphs of these counters. One such program is Munin. Munin can be found at http://munin-monitoring.org/ . There is a plugin for munin in the Varnish source code. For more information please see :ref:`ref-varnishstat`.