about Fabric capacity- how to make sure autoscaling and smoothing are enabled

[Jeanxyz]

I used Fabric F2 with my previous job, the speed seems ok most of the time. I have now purchased Fabric F2 Pay-As-You-Go using my personal account, and for some reason, the workspace seems to get throttled quite often. 

To solve the problem, I have created a customized spark pool and enabled Autoscale in workspace - Spark setting, but the problem remains. When I check my Capacity Metrics, I have the impression, there is no smoothing taking place, and there are frequent throttling taking place during some days. 

The real issues is I didn't run large spark jobs comparing with my previous job, but I definitely got more throttling with my new capacity. How can I know if smoothing has been set up with my personal capacity (isn't this enabled by default)?

[Jeanxyz]

Thanks for the explanation. I have created a new capacity with West Europe, the notebook is much faster than this time. Stupid me 🙂

[burakkaragoz]

Hi @Jeanxyz 
Glad to hear the new capacity in West Europe made a difference! No worries at all. We’ve all been there. What matters is you figured it out and got things running smoother.

Appreciate you following up, and feel free to reach out anytime if you run into anything else.

[burakkaragoz]

Hi @Jeanxyz ,

Thanks for the detailed breakdown – and those Capacity Metrics screenshots really help.

Here are a few things to clarify and check:

1. Smoothing in F2 Capacity

• Smoothing is not enabled by default on F2 Pay-As-You-Go capacities.
• It’s typically available on larger SKUs (F64 and above) or reserved capacities.
• For F2, you might see autoscale options in Spark settings, but that doesn’t guarantee smoothing at the capacity level.

2. Autoscale vs. Smoothing

• Autoscale in Spark settings only applies to Spark job execution (e.g., scaling executors).
• Smoothing is a Fabric capacity-level feature that helps absorb short-term spikes across workloads (SQL, Spark, etc.).
• If smoothing isn’t visible in your Capacity Metrics or Admin Portal, it’s likely not active for your SKU.

3. What You Can Do

• If throttling is frequent and disruptive, consider:
  • Upgrading to a higher SKU (e.g., F4 or F8) where smoothing is more effective.
  • Scheduling heavy jobs during off-peak hours.
  • Splitting workloads across time or workspaces to reduce peak pressure.

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[Jeanxyz]

Thanks for replying. You mentioned smoothing is not enabled by default on F2 capacity. Where do you find the information? I checked online, there is no mention of this. 

In general, I'm still trying to figure out why my F2 capacity is so slow. I have canceled my capacity because that capacity is registed as East US region while as a user I'm based in Europe. I have now created a new capacity with West Europe region. Based on initial test, the speed seems to go up. I will test a bit more and keep everyone posted. 

[burakkaragoz · Accepted solution]

The info about smoothing not being enabled by default on F2 comes from internal Fabric documentation and some testing experience. It’s not super clearly documented publicly (yet), which I agree can be frustrating.

Good call on switching to a region closer to your user base — latency and backend resource availability can definitely impact performance. West Europe should give you a more responsive experience if that’s where your workloads and users are based.

Keep us posted on how the new capacity performs — would be great to hear if the region switch alone made a noticeable difference.