# Dev Update Week 0

As the cohort nears its start, I’ve been reviewing the wiki and catching up on all the relevant study group videos I missed.

I’ve started thinking about which project I want to work on this cohort. I’m leaning towards something in Rust or possibly Go. As for which level of the stack, I’m relatively agnostic.

## Research Topics

The areas that piqued my interest this week were how to make Ethereum more censorship-resistant and credibly neutral, and how to improve client stability during long stretches of non-finality.

## Holesky Incident

Testnets are expected to fail and reorg, they’re testnets for a reason. Holesky was a particularly notable failure that highlighted known client issues around non-finality.

I was running validators for Holesky when the chain spiraled into non-finality. The research I did this week clarified what I’d experienced: the ballooning hot DB size in Lighthouse and other clients overwhelmed system resources. Normally, unfinalized blocks are cached only a few epochs ahead. But during prolonged non-finality, reliance on the freezer DB caused clients to OOM (Out of Memory) or run out of disk space.

These issues have long existed but haven't been a top priority. Fail-safes for rare edge cases don’t always get attention, especially when new features are in higher demand. Still, this hits home stakers the hardest, those with limited RAM and storage are most vulnerable to these non-finality events which are essentially minimum requirement spikes.

I also went through old validator logs to better understand what non-finality looks like from the client side. Inspired by Mario, I’ve started reading the eth2 book to deepen my understanding of Ethereum’s consensus and am looking into spinning up a local testnet.

## FOCIL

In researching censorship resistance, I dug into FOCIL and one alternative: BRAID. FOCIL is definitely the more mature idea, and it’s a much simpler solution than BRAID, especially regarding UX.

As for testing and implementation, 4 CL and 3 EL clients have begun work on the EIP, with many nearing public testnet readiness. Others, according to [meetfocil.eth.limo](https://meetfocil.eth.limo), haven’t started yet. With FOCIL potentially headlining Glamsterdam, it’s exciting to see core devs getting ahead on this.

I’m still concerned about potential liveness issues if proposers don’t receive the full list. Some flexibility might be needed. Also, the IL size is still under discussion ([source](https://efdn.notion.site/IL-Size-104d9895554180acb8f1da65a546598b)) and worth tracking. Will it reflect the gas limit? And if so, will it need to be updated periodically or be dynamic?

## Project Ideas of Interest

Naturally, based on my research, I’m interested in the Erigon FOCIL implementation and the Lighthouse better state cache heuristics project. The Ream projects also looked interesting, but I haven’t looked too far into them yet.

## Resources

- [Holesky Postmortem](https://github.com/ethereum/pm/blob/master/Pectra/holesky-postmortem.md)
- [How long non-finality could kill Ethereum by Dapplion | Devcon SEA](https://www.youtube.com/watch?v=z2jafwPFLaQ)
- [Censorship Insurance Markets for BRAID (EthResearch)](https://ethresear.ch/t/censorship-insurance-markets-for-braid/20288)