When designing an infrastructure, you will have a percentage of virtual machines that run applications that the business considers critical. Out of an entire virtual machine estate this could be 10% or less.
Often the critical virtual machines share the same shared storage as the non critical virtual machines. If a non critical virtual machine makes a call for 1,000 IOPS the shared storage will deliver it, but at what cost to the critical virtual machine? This effect is known as the ‘noisy neighbor’ and is flagged in most designs I carry out. Until now I have used vSphere Enterprise Plus licenses with Storage IO Control to counteract this.
Today, I had an idea for a use case, which I thought I would share with you. Maybe we can do things differently with the release of 3PAR Inform OS 3.1.3?
Rewind 3PAR Inform OS 3.1.2
In 3pAR Inform OS 3.1.2 the concept of applying quality of service to a virtual volume set was introduced. This gave you the ability to control two settings:
- I/O Limit (IO/Sec)
- Bandwidth Limit (KB/s Sec)
For me this setting was always the wrong way round as I wanted to guarantee a virtual volume set to have ‘x’ IOPS or bandwidth.
3PAR Inform OS 3.1.3 QoS
I have it on good authority that in January 2014 3PAR Inform OS 3.1.3 is having a QoS face lift. With the ability to guarantee performance to a virtual volume set.
vSphere Use Case
This is when things start to get interesting, do we need to purchase vSphere Enterprise Plus licenses for every processor socket in our physical servers to protect a small percentage of critical virtual machines? Maybe not.
Perhaps we could use the Optimization Suite from 3PAR instead. Let me walk you over my thoughts:
- Create a Thin Provisioned Virtual Volume of the appropriate space for your critical VM e.g. 1TB
- Create a Virtual Volume Set and place the Virtual Volume in this to protect your critical VM
- Create and apply the appropriate QoS rules to the Virtual Volume set e.g. Guarantee 1,000 IOPS
- Add datastores to ESXi Hosts
- Create your VM ensuring the VMDK sits on the right Virtual Volume
The result is you have a VM which is guaranteed the correct resources in times of contention without the need for SIOC in vSphere Enterprise Plus licences.