Linux guests

This topic describes the baseline settings for Linux™ guests and which rpms are installed.

Baseline settings

The baseline CPU and memory settings for the Linux guests were established.

A DayTrader workload is tested against each triplet and each combo server through an iterative process to reach load targets and optimize sizing and resource usage.

A specific load based on a number of DayTrader clients running on each triplet and each combo server is established where system-wide CPU-utilization is between 90% and 97%. Baseline memory and CPU settings, in conjunction with the established DayTrader load, represent a hand-tuned end-to-end system where the virtual CPUs and memory allocated for each guest are just sufficient to support the workload.

The number of clients for each triplet and each combo server is then kept the same throughout the tests, keeping the workload generation constant. The baseline settings are a good approximation of the ideal CPU and memory configuration for a given client-driven workload.

In the case of the dynamic runs, a second set of servers was created as an exact replica of the first set of servers. Set 2 servers were only used for the dynamic test runs and are not up during the static tests when the configuration files are evaluated.

For the tests with cpuplugd, the guest definitions were changed to 4 CPUs and 5 GB memory for all guests. Using different cpuplugd configuration files and keeping the number of DayTrader clients constant we measured how the management of CPU or virtual memory or both for systems with oversized virtual resource allocations was affected by CPU plugging and memory plugging.

Various configuration files were tested for their ability to quickly and correctly adjust virtual CPUs and memory for a particular DayTrader user count, where correctly allocated memory is as close as possible to the manually-sized configuration.

Linux service levels

The following rpms were installed during the testing of the cpuplugd daemon on top of the SUSE Linux Enterprise Server (SLES11) SP1 distribution to fix known issues relevant for this test. The s390-tools rpm contained the new version of cpuplugd:

kernel-default-2.6.32.43-0.4.1.s390x.rpm
kernel-default-base-2.6.32.43-0.4.1.s390x.rpm
kernel-default-devel-2.6.32.43-0.4.1.s390x.rpm
kernel-default-man-2.6.32.43-0.4.1.s390x.rpm
kernel-source-2.6.32.43-0.4.1.s390x.rpm
s390-tools-1.8.0-44.45.2cpuplug8.s390x.rpm