Ethereum devs push to save Holesky testnet

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The hard fork for the Pectra upgrade on Ethereum’s largest testnet, Holesky, saw the chain split in two. With validators scattered across two chains and slashing protections preventing an easy fix, the network became stuck in a state of non-finality.

Over the past week, developers have thrown everything at the problem. A coordinated slashing event was planned to purge the invalid chain and push Holesky back to finality. Yet, even with patches improving client synchronization, the validator set has remained below the 66% threshold needed for finality. While participation has climbed to 53%, developers now estimate that finality may not be reached until March 28.

The failure to finalize has sparked some debate among Ethereum’s core developers. Some, like CarlBeek, suggested in the aftermath of the bug that Holesky isn’t worth saving, and Ethereum should spin up a replacement testnet instead. Testnets are disposable, and forcing a broken network back to life could waste valuable dev resources.

Others strongly disagree. Holesky is supposed to be supported until 2027. Newly appointed EF co-executive director Tomasz Stanczak stated that making Holesky operational again is a “war mode test” for client teams. If Ethereum developers can’t restore Holesky, what does that say about their ability to maintain mainnet’s resilience?

For staking protocols like Lido, Holesky is mission-critical. Lido contributor Ivan Metrikin warned on today’s Consensus Layer call that without finalizing Holesky, testing staking integrations, monitoring and oracles become nearly impossible.

“For us, it’s really critical that it works,” Metrikin said, noting that on the plus side, Holesky will provide an opportunity to test Lido’s “bunker mode” in a production environment — a sort of silver lining.

In the near term, developers plan to fork Holesky as an additional testnet so as not to lose momentum for a Pectra mainnet launch. But to truly serve as a replacement, it would need to be as large as Holesky, with comparable validator participation, tooling and protocol deployments — an expensive and time-consuming process.

Another concern expressed on the call is that launching a new testnet would cause teams to abandon Holesky, turning it into a “second-class citizen.”

Still, this shadow fork is seen as a compromise to allow testing to proceed this month until Holesky is back on track. The shadow fork may end up serving as the primary testing ground for Pectra, as devs speculate that redistributing validator keys to fully restore Holesky could take up to a year.

It’s unclear how long teams will maintain this new shadow fork, but they did agree to spin down both Devnet 7 and the temporary Mekong testnet.

Wen Pectra?

The Holesky situation isn’t a direct risk to Ethereum — it was an edge case specific to the testnet — but it is a bad look.

And it will delay the Pectra mainnet upgrade slightly. Core developers on the call agreed not to move forward with setting a date for the fork until Holesky finalizes in a few weeks.

One positive sign is that Gnosis’ Chiado testnet implemented the Pectra fork, which was reportedly a success. The EVM-compatible Gnosis chain has historically proceeded to fork its mainnet a few weeks in advance of Ethereum.

For now, Ethereum Foundation researcher Alex Stokes — who moderated the call — signed off on an optimistic note when it comes to Holesky: “It’s been a lot of work and we’re in the middle of it, but we’ll get it back.”

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