Why AWS Lambda suggests to set up two subnets if VPC is configured?

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Is this because of the IP availability?

I've always thought that creating a single huge subnet instead of creating two with the same size, is exactly the same. I haven't experienced any perfomance issues by doing this, but I haven't found anything in the docs to confirm that this is a valid way.

Why AWS Lambda suggests to configure these two subnets? is there a technical reason for that?

Thanks in advance.

1 Answers

It is not "only" for performance, it is for high availability(more fault-tolerant) according to here

It's a best practice to create multiple private subnets across different Availability Zones for redundancy and so that Lambda can ensure high availability for your function.

Resilience documentation

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