VM live metrics in XenServer with Xen Orchestra

Olivier Lambert

• 2 min read

Because this is really important, we'll release this feature next week! As a result, this post is also about announcing Xen Orchestra 3.9.

Let's see it immediately in action:

Why performance metrics matter

The goal of live performance metrics are various. But in a Virtual Machine case, it's pretty clear:

  • you can see any problem/spike in less than 1 second
  • it's easy to read
  • it's live, so you can track a specific problem without waiting
  • it helps to debug/benchmark your infrastructure (what's limiting my application performance?)

And because XenServer is really cool, it gives us a lot of data. The challenge is to get AND display them.

Remember: metrics are not like supervision, not the same goals. But it's also a fantastic tool.

Thus, this time, imagine this scenario:

  • you are using XOA Enterprise, so you can delegate VMs to your developer team
  • they can only see their VM in Xen Orchestra, and thus their metrics
  • they can start their software, and see the impact on the VMs performances (disks, network, CPU, RAM)

Great isn't it?

Metrics in XenServer

How to fetch VM metrics/data in XenServer was already covered in this previous article: Statistics in XO. But in a few words, those metrics are stored on RRD-like files written in XML, on each the host where the VM is currently running.

Here is how it works:

  • the file is downloaded by xo-server
  • the XML is parsed
  • finally, numbers are sent to the client, in this case: xo-web.

XenServer uses multiple sample rate: last 10 minutes, the sample rate is 5 seconds. You got also last 2 hours, last week and last year, with respectively 1 minute, 1 hour and 1 day of sample rate.

In Xen Orchestra

Since last year, we planned to integrate those metrics. Our initial draft was:

And the "real" result is:

Let's zoom:

When you click on a chart, you got it on the whole panel:

This feature is also great when you make benchmarks. In this video, we'll start a disk benchmark on Windows 7 on XenServer 6.5. You'll see instantly the Disk I/O chart rocketing to the sky!

XO 3.9!

Yes, this will be the last stop before 4.0! And this 3.9 should be out Friday, the 17th. Hang on!