MRTG

Statseeker

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I was fortunate have been invited to Gestalt IT’s Network Field Day 4. I’m a systems guy so it seems odd that I’d go to a networking event, but as silos in IT fall and virtualization wants to do everything in software there’s quite a lot for a guy like me to contribute. Even if it’s just to add a different point of view to some of the network-centric discussions with vendors. Anyhow, one of the vendors we spoke with was Statseeker. They make statistics gathering software for network equipment. You might be inclined to think that network performance monitoring is a pretty dull topic, and you may have noticed that I usually don’t write specifically about products here. The …

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Statistics Rollups Are Evil

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It’s pretty common for statistics-gathering software, like MRTG, Cacti, VMware vCenter, etc. to roll statistics up over time by averaging them. This helps save space, as well as cut down on the processing needed to look at & graph the data. The problem is that the process is lossy. These systems save disk, memory, and CPU by averaging the data over longer and longer time periods. Those averages remove spikes and make the data less and less representative of what actually happened on your system or network. It also makes it damn near useless for planning and troubleshooting. Let’s start with an example I drew up in Excel to simulate something like vCenter recording an application server’s CPU load every …

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