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vSohill
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Capacity demand and usage

Hello vRO ps community,

I love vRO ps and there are many things I would like to know. My question is why workload shows (Always ) Memory usage greater than Demand and Capacity, on the other hand there is no contention.

Thanks for the help,

memory.JPG

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vSchroed
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If workload was 100% and Usage was 100% you would really be using all of the Capacity for that VM. If Workload was 120% and Usage was 100%, you need to add 20% more memory to meet the Demand for that VM.

If Workload was 25% and Usage was 100% you would really be using 25% of that memory. You still have plenty of capacity on the VM, and depending on how stable that 25% is you could probably cut the Memory in half and still be okay.

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vSchroed
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Hey vSohill,

In the charts you are looking at what you are seeing is "Workload" as kind of a section. If you checkout what VMware has to say about Workload it can sometimes be kind of confusing.

"Workload, simply put, is a measurement showing the ratio of the resource demand of a virtual object (VM, ESX, Cluster, etc) versus the amount of resources it can obtain."


Workload being the Demand vs the "the amount of resources it can obtain". That is kind of a strange statement. But what it really means is Workload equals Demand divided by Capacity (or allocated). Workload in this case is fairly low (about 25%). As Workload approaches 100%, your VM will be using up all of it's available memory. If Workload exceeds 100% you have undersized your VM, because the VM is demanding more memory than you have granted it.


What it boils down to is that Memory Workload is a very good metric to indicate what we would think of as Memory Usage, because Usage can include things that get cached and never get cleared out. So if you are measuring your VMs by Memory Usage you might notice that all of them are using all of their available memory all the time, which isn't very useful.


Does that answer your question?

vSohill
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Thanks a lot vSchroed,

Yes in that figure the workload about 25%. VM chart shows the memory usage 100% of the capacity. As I understood demand menas what the VM needs and usage is the amount of the resource the vm recived it (correct me please if I was wrong).

Let assume the workload was 100% the memory usage will still 100% of the capacity. Is that correct?

Thank you

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vSchroed
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If workload was 100% and Usage was 100% you would really be using all of the Capacity for that VM. If Workload was 120% and Usage was 100%, you need to add 20% more memory to meet the Demand for that VM.

If Workload was 25% and Usage was 100% you would really be using 25% of that memory. You still have plenty of capacity on the VM, and depending on how stable that 25% is you could probably cut the Memory in half and still be okay.

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vSohill
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Thank you,

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