Post Processing Cacti data

[adurotec]

Are there any tools available that can be used to post process the logs that are stored in the cacti DB other then using cacti graphs via the cacti front end? I am looking for memory utilization over a period of weeks, hoping to find what the peak is for our busy hour each day.

Any help in the right direction would be appreciated.

Thanks.

[Linegod]

The data is not in the Database, it is stored in the rrd files.

Use 'rrdtool' to find information in them - 'rrdtool --help'

[adurotec]

Thanks for pointing me in the right direction.

I ran:

"rrdtool fetch example_prod_com_mem_free_205.rrd MAX --start 0 --end 0"
_cache_204.rrd
_buffers_203.rrd

and got what looks like the date the data was collected and a floating point result:

1257120300: 8.0504640000e+04

Is the data in an rrd file for a 24 period? Is it possible to see per hour from the rrd files and if so, does cacti overwrite these files after 24 hours so any historical data beyond the current file is an average and not hour per hour?

[Howie]

You might also want to look at the Transporter and DSStats plugins - the first will allow you to access individual data points going back over time directly in the SQL database, and the second collates hourly/daily/weekly/monthly average/max statistics for all data sources.

To answer your question though - sort of. You should really read the RRDTool tutorial on the rrdtool.org site for how rrdtool works, because this is fundmental to the results you will get and what you should expect. The actual times used for aggregation depend on how the rrd file is defined, but essentially, yes, after a certain period you can only get averaged (aggregated) data. You can stop that happening, but at a cost of more disk space, and at least theoritically, performance.