+ collection 4 - An efficient graphing front-end for collectd
+=============================================================
+
+About
+-----
+
+ collection 4 (c4) is a web-based front-end to the RRD files updated by
+ collectd. It is designed to be highly efficient and handle large
+ installations - with 50,000 and more RRD files - well.
+
+
+Concepts
+--------
+
+ Graphs
+ ------
+ c4 lets you configure "graphs" in its config file. Each graph has a selector
+ which determines which files will be used to draw the graph. The selector
+ uses the host/plugin[-instance]/type[-instance] layout known from collectd.
+ Each field of the selector may be one of two wildcard expressions:
+
+ * "/any/"
+ The field may be any value. The files will be grouped by the values of
+ all "/any/" fields. Think of the "GROUP BY" SQL expression. Each grouping
+ is called an "instance" which can be identified by the graph selector and
+ the value of the "/any/" fields.
+
+ * "/all/"
+ As with the any-selector, the field may be any value. However, all files
+ that only differ in the "/all/" field(s) will be printed in the same
+ graph.
+
+ Upon startup, c4 will read the configuration and scan the directory
+ containing the RRD files. Each file is added to all matching graphs, either
+ by adding it to the appropriate instance or by creating a new instance. I.e.
+ each file may be used in multiple graphs.
+
+ If a file does not match any graph, a "dynamic graph" matching only that file
+ will be created. This allows the front-end to display all files even when
+ there is no explicit graph definition for them.
+
+ Data providers
+ --------------
+ The idea is to encapsulate all the functions specific to one write plugin of
+ collectd using an interface for querying data. This allows to program the
+ rest of the front-end in a way that doesn't rely on one specific storage
+ back-end.
+
+ Currently, the only data provider scans a directory for RRD files and uses
+ the librrd to fetch data. The whole concept is still a bit of a work in
+ progress and currently the code-base is still cluttered with "*_get_rrdargs"
+ functions. The RRDtool generated graphs will likely be replaced by a graphing
+ solution integrated in the C code (creating rendered graphics) and / or a
+ JavaScript-based solution which renders graphs in the browser.
+
+
+License
+-------
+
+ collection 4 is licensed under the GNU Lesser General Public License (LGPL),
+ version 2.1. The exact license terms are available in the file "COPYING" in
+ the top source directory.
+
+
+Author
+------
+
+ Florian "octo" Forster <ff at octo.it>
+
projects / collection4.git / blobdiff