When it comes to assessing fitness of purpose, even audited benchmarks are quite useless unless they incorporate failure testing alongside the load test. I helped develop the TPCx-HCI benchmark which mandates the simulation of a node failure.
We have started seeing misaligned partitions on Linux guests runnning certain HDFS distributions. How these partitions became mis-aligned is a bit of a mystery, because the only way I know how to do this on Linux is to create a partition using old DOS format like this (using -c=dos and -u=cylinders) Continue reading “The return of misaligned IO”
Often we are presented with a vCenter screenshot, and an observation that there are “high latency spikes”. In the example, the response time is indeed quite high – around 80ms. Continue reading “High Response time and low throughput in vCenter performance charts.”