From: Florian Forster Date: Mon, 21 Jun 2010 21:05:58 +0000 (+0200) Subject: README: Explain "graphs" and "instances" a little. X-Git-Tag: v4.0.0~201 X-Git-Url: https://git.octo.it/?p=collection4.git;a=commitdiff_plain;h=998940bb79e55b8943731d1ce9b21831148f8235 README: Explain "graphs" and "instances" a little. --- diff --git a/README b/README index e69de29..6e25d3f 100644 --- a/README +++ b/README @@ -0,0 +1,41 @@ + 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 +-------- + + 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. + + +Author +------ + + Florian "octo" Forster +