The recent release of XenServer 6.1 came with what I thought was a really useful supplemental pack that allowed a large range of metrics to be monitored on XenServer hosts.

The Performance Monitoring Enhancements Supplemental Pack provides additional RRD metrics such as I/O throughput and latency that can be viewed in XenCenter. I was really pleased to see us put this in. It was functionality people really wanted and needed and so we made a conscious decision to try and satisfy the customer demand on shorter than normal time-scales (hence the deployment via supplemental pack).

A new utility was also provided, the rrd2csv tool, which will log RRDs to Comma Separated Values (CSV) format. This was provided in response to user requests for a lightweight alternative to the standard RRD xml format. The full details of the supplemental pack can be found in http://support.citrix.com/article/CTX135033.

However, a few users have reported that the metrics didn’t show up. We looked into the server status reports (bugtools) collected from these users and found that the metrics don’t work on certain configurations with certain types of storage. We’re working on fixing this, and will re-release the supplemental pack soon. On many systems (which included our test boxes!), you will see no problems, so it’s still worth trying out the pack if you’re interested.

If you’re developing utilities or applications on top of the functionality, setting up a test box should allow you to work around the issue and see the metrics available and their format. We suggest a simple test configuration, which we know works without issues: using just LVHD-based SRs and avoid other types of storage for now (this includes ensuring there are no ISOs attached to VMs).

As ever, it goes to show that if you do have a problem with XenServer, giving us the bugtools usually leads to a faster resolution. My colleagues have already posted on how you can help us sort out problems (and your help is really appreciated), see /blogs/2012/07/16/writing-good-bug-reports-for-xenserver/.