I will be at the CMG Greater Atlanta Spring conference on April 27, 2011. I was asked to cover something for both veterans and newcomers to capacity planning—along the lines of my Guerrilla Boot Camp classes. So, here's what I came up with.
Guerrilla CaP for Noobs and Nerds
Whether you're a newbie (noob) or a veteran (nerd) when it comes to capacity planning (CaP) and performance analysis, it never hurts to revisit the fundamentals. However, some CaP concepts that are touted as fundamental are actually myths. Here are some myths I hear all too often.
During my twin session I will take these myths apart to expose the facts in terms of
- We don't need no stinkin' CaP, just more cheap servers.
- CPU utilization should never exceed 70% busy.
- A well-consolidated server should have no idle cycles.
- Throughput and latency are independent metrics that must be measured separately.
- Optimal response time is achieved at the knee of the curve.
- If you can measure it, you can manage it.
Along the way, I'll offer some Guerrilla mantras, as seen in my Guerrilla book and generated automatically on Twitter. You can use them as weapons of mass instruction to bust any other myths held by your colleagues and managers, whether you're a noob or nerd.
- If the app is single-threaded, a boat-load of cheap servers from China won't help.
- A 64-way server running 70% busy is 25% underutilized.
- A consolidated server may need to be under 10% busy to meet app SLAs.
- Throughput and latency are inversely related ... always!
- Response time knees are an optical illusion.
- All performance measurements are wrong by definition.
† With apologies to Paris Hilton.