Curriculum·J313 Mining, Validating, and Running Infrastructure·about 32 min
Node operation as a user
By the end of this lesson you can
- →Separate what a node does from what an RPC provider does on your behalf
- →Compute the client share at which a single bug can stop finality
- →Price running your own node against what it actually changes
- →Decide honestly whether you should run one, and say why
Junior · enrolled learners
This lesson opens with Ethereum non-finality, 11 and 12 May 2023.
- What happened
- On 11 May 2023 at about 20:19 UTC Ethereum mainnet suffered a shortfall in block production that delayed finalisation for four epochs, roughly 25 minutes. The same pattern recurred the following day for nine epochs, roughly an hour, this time incurring inactivity penalties. The cause was high load on some consensus layer clients, specifically Prysm and Teku, triggered by an unusual scenario involving blocks carrying old attestations. Core developers released patches for both clients. Throughout both incidents the chain continued producing blocks and end users continued transacting, because the clients that were not affected kept attesting, and the network recovered without any intervention.
- The decision point
- The chain did not stop and no funds moved anywhere they should not have. What actually happened is that a bug in two client implementations degraded a property of the network, and the reason it was a degradation rather than a halt is that enough validators were running something else. Client diversity is not a governance preference. It is the parameter that decided whether this was an inconvenience or an outage.
What you will be able to answer
- →What does an RPC provider do for you?
- →At what client share can one bug stop finality?
- →What does running a node cost?
- →What does it not do?
Orientation and Year One are open: anyone can read them without an account. From Year Two onward the lessons are for enrolled learners, because progress through the later years only means anything if it is tracked against a record.
It is free. We do not sell the list and there is nothing to buy at the end of it.
Sources and review
- https://medium.com/offchainlabs/post-mortem-report-ethereum-mainnet-finality-05-11-2023-95e271dfd8b2
- https://www.coindesk.com/tech/2023/05/11/ethereum-mainnet-was-unable-to-fully-finalize-transactions-for-25-minutes
- https://www.coindesk.com/tech/2023/05/12/ethereum-resumes-finalizing-blocks-after-second-performance-hiccup-in-24-hours
- https://etherworld.co/2023/05/13/non-finality-inactivity-leak-but-ethereum-didnt-stop/
Confidence high·Volatility medium·Reviewed 2026-08-06·Owner unassigned
Contested
Reported durations for the second incident range from about 57 minutes, being nine epochs at 6.4 minutes each, to over an hour depending on what is measured from. The epoch counts come from the post-mortem and the derived minutes are stated as derived.
F101-04 owns the November 2020 Infura outage and the Geth split as an autopsy about depending on infrastructure you do not run. This lesson uses the May 2023 finality incidents to cover client diversity as a parameter and node operation as a user-side decision. Keep the split and do not re-derive the Infura argument here.
Client market shares move continuously and are estimated rather than measured, since a validator's client is inferred from behavior. The thresholds in part two are protocol properties and are stable. The shares are not.