Cluster Startup Time in Fabric Notebook Varies Across Workspaces Despite Shared Capacity

[Bhargava05]

Hi Fabric Community,

I’ve noticed something curious in my Microsoft Fabric environment and wanted to get insights or confirmation from others who might have experienced the same.

I have multiple workspaces in Fabric, and each of them contains notebooks. All these workspaces are tagged to the same capacity, yet I’m seeing different cluster startup times when running notebooks across them.

For example, a notebook in Workspace A starts up noticeably faster than a similar one in Workspace B, even though both are under the same capacity and have similar workloads. I’ve ruled out obvious differences like notebook complexity or library dependencies.

So my question is:
Why would cluster startup times vary across workspaces that share the same capacity?

Would love to hear from others who’ve seen this or have insights into how Fabric handles cluster provisioning across shared capacity environments.

Thanks in advance!

[v-saisrao-msft]

Hi @Bhargava05,

We haven’t heard back from you in a while regarding your issue. let us know if your issue has been resolved or if you still require support.

Thank you.

[v-saisrao-msft]

Hi @Bhargava05,

Checking in to see if your issue has been resolved. let us know if you still need any assistance.

Thank you.

[v-saisrao-msft]

Hi @Bhargava05,

Have you had a chance to review the solution we shared by @tayloramy ? If the issue persists, feel free to reply so we can help further.

Thank you.

[tayloramy · Accepted solution]

Hi @Bhargava05, 

How much varience are you seeing in start up times? 
I also seem some varience, but usually not much. All my sessions usually start in under a minute.  

Some of the things that impact it are if the resources are warm or cold, whether you've set custom spark pools or are using the starter pool, and how many other spark sessions you have running in the background or for other processes. 

If you found this helpful, consider giving some Kudos. If I answered your question or solved your problem, mark this post as the solution.

[tayloramy]

Hi @Bhargava05, 

Are you using the default environment or custom environments? 

See this similar forum post if you are using custom environments: Solved: Re: Spark session takes 15 minutes to start when a... - Microsoft Fabric Community

If you found this helpful, consider giving some Kudos. If I answered your question or solved your problem, mark this post as the solution.

[Bhargava05]

@tayloramy 

Im using default environment.