Have you ever received some complaints from either the user community or the help desk indicating the performance on the servers running in your XenServer environment is a bit lacking? I’m sure your first thought is “what ever” I know I built the XenServer Resource Pool with enough horsepower to handle way more than the current workload and then some (N+1 you know). But then shortly after that thought it starts to eat at you and curiosity gets the best of you. So you fire up XenCenter and start looking at the various performance counters on the hosts and subsequently each of the VMs but this is taking up too much time and you think there has to be a better way. Well today is your lucky day because there is and first off it is free and secondly it is a pretty easy utility to use. The command is called xentop which can be accessed either through XenCenter’s access to the host’s console or through the use of an SSH client like PuTTY. I prefer to use PuTTY since the ability to re-size the screen makes for an easier to read display of all of the VMs running than the console window in XenCenter even if you use the scale option or un-dock the window.
As with most commands there is a help option accessible through the use of the command “info xentop” without the quotes of course. You can fire up xentop with or without command line options depending on what you are trying to accomplish or needing to see. By default the statistics are being updated every three seconds but this can be changed by pressing the D key and enter your desired delay (delay between updates) and hit enter. There are a series keys listed across the bottom of the screen which will turn on and off those performance counters. So by pressing the N key it will add network counters and V will add the vCPU counters. If you want to remove those counters just by pressing the key again will turn them off.
Citrix support has a write-up on this utility which is worth referencing since it lays out in a basic sense what the column descriptions are and provides a screenshot of the utility in action. This article can be found here http://support.citrix.com/article/CTX127896
I would recommend trying this utility out and becoming more familiar with this so your time spent trying to find the offending VM will not take you as long going forward.