Archive for August, 2007
Removing spikes from RRD databases
Friday, August 31st, 2007
RRDs are fixed size databases for storing time series data. They collect information given to them and normalize it to permit trending over long periods of time.
Spurious data may inadvertently make it’s way into a database. Treating this data is possible using the following means:
- Set the rrd-min and/or rrd-max variable(s) for each datasource when creating new RRD databases
- Use rrdtool dump to export the RRD database to XML format, edit out the spurious values and import the data back into the RRD database
- Use rrd tune to apply rrd-min and/or rrd-max variable(s) to an existing RRD database. All values outside the minimum or maximum defined bounds will be set to NaN.
rrdtool tune <file> --maximum <ds>:<value>
- Use the perl script removespikes.pl. This would remove all spikes within 1% of the datapoints in the rrd file. If 1% does not fix them, modify the % value up until all the spikes are removed. Though this may eat up some valid values in the process, use with caution!
perl removespikes.pl -l 1 fastrouter_ethernet0_1.rrd
- Use rrd_editor, a cross platform win32 or perl/tk tool to seek and remove spikes in an RRD. I have not used the tool, but according to comments it works as advertised. It also lets you easily add or remove RRAs and datasources from an RRD, which is a golden feature for many of us.
- Use killspike2 an RRD spike removal script distributed as part of the Cricket network management system. I have not used the script, but it is known to work.
As with any solution, automation and prevention are the keys to a fluid system.
genDevConfig will automatically set rrd-min and rrd-max values for all config-tree targets it creates for Cricket.
Download Cricket configuration generators
Wednesday, August 29th, 2007
Download the latest release candidate version of genDevConfig.
Or, download the latest stable version of genRtrConfig.
To learn more about the Cricket configuration generator for SNMP managed devices, please consult the genDevConfig reference manual.
To learn more about high performance trending of time series using Cricket, please visit cricket.sourceforge.net.
Also of interest, an older configuration generator project, CHIRP, has support for some equipment that is not currently fully supported in genDevConfig (Fore ASX, NetScaler, HP AdvanceStack, Riverstone, Foundry BigIron). The perl modules for those device classes included in the CHIRP tool can be easily converted to genDevConfig modules. See the genDevConfig reference manual linked above.
Acktomic.com changes
Tuesday, August 7th, 2007
- Moved to new hosting platform.
- Put up Cricket Network monitoring extension resources for genDevConfig, genRtrConfig and genAutoConfig .
- Blog about network management and security using open-source and/or commercial products.
- New layout for presenting professional services
- Offer additional development resources and tools for the cricket SNMP network management system
- Provide development resources and tools for the rancid configuration management tool for network devices
Most previously available resources will be put back online. In addition, new white papers and tools will also be added. It is my aim that the site provide pertinent information and technical insight into practical network and security using available tools and processes.
Francois Mikus