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1-0-1
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Full Name: Bernd
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VMware Optimization report for oversized VMs

Post by 1-0-1 »

So I thought I had a good grasp on active memory and consumed memory in regards to VMware Virtual Host memory usage. My aim was to have something I could go by for right-sizing our virtual machines as a lot off workloads has been reduced and we sitting with bloated virtual machines.

I thought the consumed memory counter based report would be the best. I am however concerned with the huge difference between the consumed vs active memory based "Oversized VMs" report. I know for a fact that the consumed memory report's recommended makes more sense in terms of reducing memory because the given virtual server had almost all of their guest based workloads moved off. However - the active memory based report has not a single memory reducation recommendation. What is more confussing is that the "Undersized VMs" report (consumed memory) gives me extremly contradicting recommendation to the "Oversized VMs" e.g. in the "Oversized VMs" report a VM should be allocated only 4.5 GB of RAM (originally has 16GB) but in the "Undersized VMs" report should not be allocated less than 20 GB of RAM.

My sample I obtained from a 6 months period between 8:00 - 17:00 (I would assume it leaves out weekends?). I played with the time/date intervals around and they do not make much of a differene. So in that regards I am comfortable with the results.

Some of the memory reducation recommended are however well below the given workload vendor minimum recommended memory allocation. Does servers I will only reduce down to the vendor's recommended memory allocation.
1-0-1
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Full Name: Bernd
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Re: VMware Optimization report for oversized VMs

Post by 1-0-1 » 1 person likes this post

So I must have confused something here because I ran the two reports again and used consumed memory as a measuring method. Consumed memory makes more sense in my case as I want to gauge the relative capacity of my virtual hosts and weather I can make due with one less. Since consumed memory includes memory used by vShpere Services and Management agents and VMKernel.

The two reports (oversized vs undersized) now makes more sense. Moral of the story - do not multitask when making capacity decision :)
RomanK
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Re: VMware Optimization report for oversized VMs

Post by RomanK » 1 person likes this post

Hello Bernd

Happy to know that all is clear now.

Consumed and used memory are described in this VMware KB. Having that, indeed, consumed memory metric would be your choice.

Thanks.
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