DRS Doctor-VMware Flings

VMware has released a new flings DRS Doctor on June 29, 2016 by VMware Labs team. DRS Flings, will monitor your DRS clusters for virtual machine and host resource usage data, DRS-recommended migrations, and the reason behind each migration. It also monitors all the cluster-related events, tasks, and cluster balance, and logs all this information into a plain text log file that anyone can read.

What is VMware DRS?

VMware DRS is a feature that enables a virtual environment to dynamically balances computing capacity across a collection of hardware resources aggregated into logical resource pools, continuously monitoring utilization across resource pools and intelligently allocating available resources among the virtual machines based on pre-defined rules that reflect business needs and changing priorities. When a virtual machine experiences an increased load, VMware DRS automatically allocates additional resources by redistributing virtual machines among the physical servers in the resource pool.

Below are the goals of DRS:

  • At startup, DRS attempts to place each VM on the host that is best suited to run that virtual machine.
  • While a VM is running, DRS seeks to provide that VM with the required hardware resources while minimizing the amount of contention for those resources in an effort to maintain balanced utilization levels.

If a DRS cluster will become unbalanced, DRS can migrate VMs from over utilized ESXi hosts to underutilized hosts. DRS performs those migrations of VMs across hosts in the cluster without any downtime through using vMotion. you may decide whether DRS will simply show migration hints or automatically perform the migration when the cluster turns into unbalanced by defining the automation level.

Now let’s talk about the new fling DRS Doctor

So What is DRS Doctor?

DRS Doctor is a command line tool that can be used to diagnose DRS behavior in VMware vCenter clusters. When run against a DRS enabled cluster, it records information regarding the state of the cluster, the work load distribution, DRS moves, etc., in an easy to read log format.

The goal of DRS Doctor is to give VI admins better insight into DRS and the actions it performs. It is very useful for analyzing DRS actions and troubleshooting issues with very little overhead. This is also an easy way for support engineers to read into customer environments without having to rely on developers to debug DrmDump logs in order to troubleshoot simple DRS issues.

DRS Doctor connects to the vCenter server and tracks the list of cluster related tasks and actions. It also tracks DRS recommendations generated and reasons for each recommendation, which is currently only available in a hard-to-read format in DrmDump files. At the end of each log, it dumps the Host and VM resource consumption data to give a quick overview of cluster state. It also provides an operational audit at the end of each log file.

Prerequisites for Installation:

  • Requires Python 2.7.6 or higher
  • Requires Python modules “pyyaml” and “pyvmomi”

How to Deploy DRS Doctor:

  • Install python 2.7.6 or higher.
  • Install python modules “pyyaml” and “pyvmomi”
  • Review the ReadMe.txt in the source folder on how to configure and run the tool against your VC. The configuration is pretty straight forward.
  • If you need to install pyvmomi, you can install with “pip install pyvmomi”

Note: For installation steps on CentOS 6.5, please see the linked pdf.


Mathew Meyer from VMware explained in very details about the New Fling- DRS Doctor in VMware vSphere Blog – click here 

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