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RRD Manager - RRD Collector |
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Round Robin Archive - RRA
Round Robin Archive (RRA) contains a limited number of consolidated data. The consolidation consist of a mathematical calculation or a logical selection on collected samples (rimary Data Point - PDP).
In the example below the consolidation of 5 sample, one sample collected per minute.
The round robin archive Edition dialog box is displayed. The round robin archive RRA creation or edition window allows you to define a new round robin archive RRA entry or to modify an existing RRA.
Here under an example of round robin archive RRA open in edit mode and already configured.
If the Novice level is selected you the RRA setting is very simple. You should only select the round robin archive RRA time span and the software chooses the appropriate parameters.
If you choose the Expert mode you should specify all the settings or modify the default Time Span setting.
The first parameter is the round robin archive RRA name itself. This parameter is use in the profile configuration XML file to identify each RRA entry for a specific profile.
You should enter a name without symbol or space characters.
round robin archive name
RRA Time Span helps you to define automatically the two main parameters that describe an RRA, the “rows” and “sa” parameters.
If the Update Interval set in Global Properties tab is defined, the RRA Time Span combo defines the number of samples (PDP) to store and the number of sample PDP used by the consolidation function.
The options are:
| Option |
Update Interval |
Samples to store (row) |
Samples use in the consolidation |
Precision (time between two points) |
| 1 hour |
1 mn |
60 |
1 |
1 mn |
| 2 hours |
1 mn |
120 |
1 |
1 mn |
| 6 hours |
1 mn |
360 |
1 |
1 mn |
| 8 hours |
1 mn |
480 |
1 |
1 mn |
| 12 hours |
1 mn |
360 |
2 |
2 mn |
| 1 day |
1 mn |
360 |
4 |
4 mn |
| 7 days |
1 mn |
336 |
30 |
30 mn |
| 15 days |
1 mn |
336 |
60 |
1 hour |
| 1 month |
1 mn |
336 |
120 |
2 hours |
| 2 months |
1 mn |
336 |
240 |
4 hours |
| 1 year |
1 mn |
336 |
1440 |
1 day |
The options offered here are arbitrary; you can define your own setting in expert mode.
Parameter description:
| Number of sample to store (rows) |
The Number of samples to store sets the maximum number of “records” reserved in the database (remember that RRA has a fixed size) for each Data Source defined |
| Samples in consolidation |
The consolidation function is applied to a predefined number of samples (PDP in the RRD terminology). More samples you take less granularity you get, smaller is your database size. |
| Consolidation function |
A mathematical or simple expression is applied to a set of samples (PDP). AVERAGE : Sum the samples and dived by the number of samples. LAST : keep the last value (newest) of the set MAX : keep the highest value of the set MIN : keep the lowest value of the set |
| Xfiles factor |
The xfiles factor defines how many PDP in the consolidation function can be UNKNOWN before considering the result of this consolidation as UNKNOWN. BY default at least one sample on two (0.5) should not be in UNKNWON state. |
| Description |
A description field that best explains what is the RRA goal. |
When you are in expert mode, the Time Span value is automatically calculated.
In the following example we choose to store 6 month of Data with a granularity of 5 minutes.
If we perform a preliminary evaluation we get:
6 month * 31 days * 24 hours * 60 mn = 267840 mn.
267840 / 5 = 53568 samples to store
We can now set the number of sample and the number of samples used in the consolidation function
round robin archive Edition
RRA Edition is not recommended if you have already use the profile for a DataBase creation. A LoriotPro Database configuration file keeps a link to the profile used at the creation step. If you modify RRA profile the database structure is not the same as what the profile describes.
To edit an existing RRA you should select one in the list and click the Edit Archive button. A double click on a line opens the editor too.
If you save the round robin archive RRA, a warning is displayed, click on cancel if you are unsure of what you are modifying.
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