Ethereum Resumes Finalizing Blocks after Second Performance Hiccup in 24 Hours

The Ethereum blockchain suffered from a technical issue on Friday that caused the network to stop finalizing blocks for over an hour, the second such outage in the past 24 hours.

The incident – the cause of which remains a matter of speculation – sparked major security concerns for users of the second-largest blockchain by market capitalization. According to the Ethereum Foundation, when blocks are not being finalized, it is possible that pending transactions might be re-ordered or dropped from the network.

The network had resumed finalizing blocks at press time, but this is the second time Ethereum has seen a hit to its performance in 24 hours – the chain experienced the same issue Thursday, when finality paused for roughly 25 minutes.

Questions about Ethereum's stability could stain its credibility in the eyes of builders. Network reliability is important for blockchains looking to attract users and capital, and Ethereum has historically been viewed as among the most stable networks on the market.

"I wouldn't say I am concerned but it's definitely not ideal," Toghrul Maharramov, a developer at the Ethereum infrastructure startup Scroll, wrote in a message to CoinDesk. "To be able to say whether or not the situation is the fault of the protocol design or an outcome of a bug, we need to first understand what actually happened."

Superphiz.eth, a self-proclaimed “Ethereum Beacon Chain community health consultant,” clarified on Twitter that transactions do not halt as a result of finality issues like those Ethereum experienced over the past couple of days. The lack of finality technically had “zero impact on-chain activity,” he tweeted after yesterday's hiccup.

Some of the services built atop Ethereum – which hosts a multi-billion-dollar network of financial infrastructure and other applications – may be forced to modify operations as a result of finality issues, however. DYdX, a leading crypto exchange platform, says it paused deposits temporarily today due to the lack of Ethereum finality and was “continuing to monitor and investigate this issue.”

"The second wave is over, but I fully expect a third," Superphiz.eth tweeted after today's incident, advising the validators that operate the network to "Increase your hardware spec if you can, switch to a minority client if you can. Apply patches when they're available."

"But really don't worry too much," he added. "As bad as this looks, the chain keeps going and eventually finalizes."

UPDATE (May 12, 2023 20:05 UTC): Adds context throughout and a comment from Scroll developer Toghrul Maharramo