Why is 5MB the limit for the block length?

Question

The length limit for each block in Polkadot is set to 5Mb as seen in the code.

But why exactly 5Mb? Could you point me to the decision process or the benchmark results for that exact value?

Thanks!

Answer 1

The formal definition and reasoning can be found in W3F's Polkadot spec, specifically Definition 158 on Block Limits:

• https://spec.polkadot.network/#defn-polkadot-block-limits

And more info from Web3 Foundation's research can be found here:

• https://research.web3.foundation/en/latest/polkadot/overview/2-token-economics.html#limits-on-resource-usage