VM vCPU and Memory Recommendations from VMware Aria Operations

Brock Peterson
Sep 7, 2023
2 min read

Rightsizing VMs is a core capability of VMware Aria Operations and has been detailed nicely here by VMware Senior Product Line Manager Brandon Gordon. The Aria Operations rightsizing engine tells us how many vCPU and how much Memory to add or remove to VMs based on past performance and consumption. This can be explored from Optimize - Rightsize.

We show Allocated vCPU and Memory and Recommended vCPU and Memory Reductions/Increases, but not the Recommended vCPU or Memory. If you look into VM metric details, you'll find that we provide CPU and Memory Recommendations designed to keep those metrics in a time remaining green state. But, we don't provide the actual number of vCPU being recommended or the amount of Memory being recommended. For those, we need Super Metrics: we'll take the Allocated Amount and add/subtract the Recommended Increase/Reduction.

Let's create four Super Metrics, one for each situation:

vCPU Recommended (oversized VMs)
vCPU Recommended (undersized VMs)
Memory Recommended (oversized VMs)
Memory Recommended (undersized VMs)

Go to Configure - Super Metrics - ADD - give your Super Metric a name and assign an Object Type (Virtual Machines in this case).

Next define the Formula: in this case we'll take Allocated vCPU and subtract Oversized vCPU from it. Then activate it in the desired Policy/s.

You can VALIDATE and/or PREVIEW in the Formula tab, but let's have a look at the Super Metric in the wild. Back on the Optimize - Rightsize page, find an Oversized VM.

Let's explore the VM called vr83-bpeterson.tvs.vmware.com. The Aria Operations rightsizing engine is recommending we reduce the number of vCPU from 24 to 12. Our Super Metric should reflect this, let's look.

Number of Allocated vCPU is at the top (24) and the number of Recommended vCPU is the Super Metric at the bottom (12), which is what we expected.

The three other Super Metrics are similar, they look like this.

Give them a minute to calculate and you'll see them against your VMs. Let's explore a VM that needs more Memory.

This VM has 16GB Memory, but Aria Operations is recommending 2GB additional, which is reflected by our Super Metric here.

You'll notice I've assigned KB as the Memory unit, but you can convert that to GB in Metric Charts and Views.

Go to VMware {code} to download these Super Metrics! Once imported, you can start using them in Metric Charts, Views, Reports, and more...enjoy.

3 Comments

Matt Woolery

Oct 21, 2024

I've noticed recently that Aria is recommending all SQL servers receive more memory. As we all know, MSSQL is designed to utilize all available memory - is there a way to override Aria's default analysis? Just because i have a MSSQL server with 128GB using 95%, doesn't mean that it necessarily needs to be bumped up. I know i can create policies to adjust thresholds and capacity, but i don't see an option for sizing recommendations.

Thanks

Edited

Alonso Trejo-Mora

Jun 19

Replying to

Hi Matt, this is an excellent question and opportunity to highlight where Ops’s recommendation engine (and virtual infrastructure resource monitoring engines in general that I’ve seen) hit a limit.

MSSQL is particularly tricky because a lot of its memory hogging (essentially) shows as Active Memory for caching.

So the tools need to see “beyond” vCenter data into the App itself to see how efficiently it’s using that Active Memory for caching.

The OOTB rightsizing tool isn’t built with these added MSSQL metrics in mind, so at this time, the best approach is to exclude the VMs from showing in the classic recommendation list and instead create your own performance View(s) using MSSQL data which you can get using either Telegraf…

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3 Comments