Xenserver RRDs

Xenserver所使用的RRD Consolidation Function(CF)共有:
1. Average
2. Min
3. Max

There exist RRDs for individual VMs (including dom0) and the host. The VM RRDs are stored on the host on which they run, or the pool master when they are not running. This means that the location of VM must be known in order to retrieve the associated performance data.

DS Field Definitions:

DS	Defines a Data Source Field.
DS-Name	The name of this Data Source.
DST	Defines the Data Source Type. Can be GAUGE, COUNTER, DERIVE or ABSOLUTE.
HeartBeat	Defines the minimum heartbeat, the maximum number of seconds that can go by before a DS value is considered unknown.
Min	The minimum acceptable value. Values less than this number are considered unknown. This is optional.
Max	The maximum acceptable value. Values exceeding this number are considered unknown. This is optional.

DS欄位格式為"三文字，三數字"

ex:
DS:telnet:COUNTER:600:0:100000000
      (DS-Name) (DST) (HeartBeat)  (Min) (Max)

RRA

RRA means round robin archive. Defining an RRA is the tricky part!

This parameter describes how long you want to hold your data, and in what resolution. There can be more than on archive. If the time span of an archive is full, the data will be consolidated and saved into the next archive.

The format is

RRA:CF:xff:steps:rows

http://community.citrix.com/display/xs/Graphing+RRD+with+GNUPlot
http://community.citrix.com/display/xs/Getting+the+Last+RRD+Datapoints
http://community.citrix.com/display/xs/Using+XenServer+RRDs