Importing Citrix XenServer Performance Data into Login VSI
When doing tests using Login VSI, external data can be imported into the Login VSI Analyzer. By importing this external data, you get full insight on your environment’s performance. On VMware vSphere, for example, esxtop can be used to collect performance data about VMware vSphere hosts. This performance data contains data about host CPU usage, memory usage or disk I/O.
In Citrix XenServer environments, the host performance data can be viewed in the Performance tab of XenCenter. However, the data can’t be exported from XenCenter itself. The data used in the Performance tab of XenCenter can be gathered on the host level using RRD2CSV.
Gathering host performance data
RRD2CSV is available by default on XenServer 6.2 and up. When using XenServer 6.1, the Performance Monitoring Enhancements Pack can be downloaded from the Citrix website. The tool can be used either by logging on through an SSH connection (using a tool like Putty) or by opening XenCenter, selecting the specific host and opening the Console tab.
Once logged on, the performance data can be gathered by entering the following command:
rrd2csv -n -s 30 :host:: > /root/VSI_Host_Data.csv
This command will output all enabled host performance metrics to a file called /root/VSI_Host_Data.csv. The first command line argument used is “-n”, meaning that the output will display metric names instead of GUIDs for CSV header values. The “-s 30” means that the RRD2CSV command will output the performance metrics every 30 seconds.
The downside of the RRD2CSV tool is that a total run time can’t be specified, like you can with esxtop. With RRD2CSV you will need to stop the gathering of performance data manually after the test has been completed. This can be done by pressing CTRL+C on the command line (either in the remote SSH session, or the Console tab of XenCenter). Once gathering of the performance data has finished, the file can be downloaded using a tool like WinSCP.
Performance tab in Citrix XenCenter
The command noted above gathers all host performance metrics which are enabled on the XenServer host. The easiest way to enable or disable performance metrics is by using the Performance tab of XenCenter. If metrics are added to an existing or new chart, the metrics will be gathered by the RRD2CSV command automatically. For example, if an NVIDIA GRID card has been installed in the XenServer host, the GPU performance metrics are interesting to gather. The GPU utilization metrics are not gathered by default--these will need to be enabled in the Performance tab of XenCenter.
Importing data into Login VSI
Once the generated CSV file has been downloaded using WinSCP, it can be imported into the Login VSI Analyzer. Start by opening the Login VSI test data in the Login VSI Analyzer. When the VSImax data has been loaded, the external data can be imported.
With the VSImax data loaded, press File > Import > External data (or press CTRL+X). Now select the CSV file generated by RRD2CSV and click Open. A window will be shown where the performance metrics can be selected. For example, the AVERAGE:host::cpu_avg field is the total average CPU utilization of the host. Select one or more performance metrics and click Open. The external data will be merged with the VSImax data to get full insight in the host’s performance.
Import external data metrics in the Login VSI Analyzer
In some cases the local time on the XenServer host is different than the time of the target machines on which the Login VSI test has been executed. The external data chart can be moved over time by clicking the Move button underneath the chart and adjusting the time. By changing the time, the external data chart is moved directly. This way, the external data can be aligned with the VSImax data.
External data and Login VSI data in the VSImax chart
Getting full insight in the host performance during a Login VSI test is key when doing performance bottleneck analysis. RRD2CSV proves to be an excellent tool to gather host-level performance metrics on XenServer. By importing the data into the Login VSI Analyzer, VSImax data and host performance metrics can be correlated to find performance bottlenecks.