Monday, 24 October 2016

5 Top Performance and Capacity Concerns for VMware - Monitoring Memory

Memory still seems to be the item that prompts most upgrades, with VM’s running out of memory before running out of vCPU.

It’s not just a question of how much of it is being used as there are different ways of monitoring it. Some of the things that you are going to need to consider are:




       Shared Pages

       Active Memory

       Memory Available for VMs

VM Memory Occupancy

In terms of occupancy the sorts of things that you will want to look at are:

       Average Memory overhead

       Average Memory used by the VM(active memory)

       Average Memory shared

       Average amount of host memory consumed by the VM

       Average memory granted to the VM

In this instance we can see that the pink area is active memory and we can note that the average amount of host memory used by this VM increases at certain points in the chart.
VM Memory Performance
It's useful to produce a performance graph for memory where you can compare:
       Average memory reclaimed
       Average memory swapped
       Memory limit
       Memory reservation
       Average amount of host memory consumed.
As illustrated below.

In this instance we can see that this particular VM had around 2.5gb of memory ‘stolen’ from it by the balloon driver (vmmemctrl), at the same time swapping was occurring and this could cause performance problems.
The next place to look at for memory issues is at the Cluster and I'll deal with this on Wednesday.
In the meantime don't forget to book your place on our VMware vSphere Capacity & Performance Essentials workshop taking place in December
Phil Bell

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