Ethereum Fusaka upgrade goes live, bringing eightfold increase in ‘blob’ capacity

Ethereum underwent its second major upgrade of the year on Wednesday, further reducing the cost of transactions on affiliated layer 2 blockchains while improving user experience and hardening the network against a common exploit.

The upgrade, codenamed Fusaka, also sets the stage for future upgrades that could increase the throughput of Ethereum itself.

Since the Merge, the network’s momentous 2022 upgrade, improvements have come at an annual clip. But a crisis of confidence early this year has led to renewed urgency among Ethereum developers, and Fusaka’s release comes just seven months after the previous upgrade, Pectra.

While highly decentralised, Ethereum has long faced a major barrier to mass adoption: it gets congested, sending transaction fees soaring. Layer 2 blockchains have emerged as a workaround, processing transactions affordably while using Ethereum as a settlement layer.

Fusaka’s chief feature is a substantial increase in the amount of data that layer 2 blockchains can send to Ethereum.

“It’s this new technique that people have been working on for a very long time,” Alex Stokes, Ethereum Foundation, said on a livestream hosted by EthStaker on Wednesday. “It lets us scale while not compromising on the values that are so important to Ethereum.”

Layer 2s send packets of data known as blobs to Ethereum for settlement. Fusaka introduces a concept known as peer data availability sampling, or PeerDAS, which allows individual nodes to store a fraction of blob data without compromising their ability to verify the entirety of that data.

Layer 2 blockchains can currently send a maximum of 9 blobs per block. After Wednesday’s upgrade, Ethereum’s blob capacity will jump eightfold, though increases will be implemented slowly in a series of smaller upgrades enabled by Fusaka.

“We could say here, in just a few minutes, dial this knob up 8x,” Stokes said. “Given this is a very new technique, and we’re not sure how the network will respond, this is not the wisest decision.”

The first mini-upgrade is scheduled for December 9 and will increase maximum blob capacity to 15. A second upgrade scheduled for January 7 will increase max capacity to 21 blobs per block.

According to Ethereum co-founder Vitalik Buterin, PeerDAS could eventually make it cheaper to transact on Ethereum itself.

“We think of blobs as being for L2s,” he said on the livestream Wednesday. “In the long term, we want to dump L1 data into blobs as well.”

Other improvements in Fusaka will allow users to sign transactions using biometrics — leveraging smartphones’ facial recognition technology, for example — and will harden Ethereum against denial-of-service attackers, who attempt to render the network useless by clogging it with a flood of spam transactions.

“There are, like PeerDAS in here, a pile of strategic upgrades that frankly are not going to be visible tomorrow,” Paul Brody, of the Enterprise Ethereum Alliance, said on the livestream.

“We actually already have more network transaction capacity than we really need. But we are laying the foundation on the road to a trillion transactions a day, and we will need every single [upgrade] by the time we are done.”

Ethereum’s next major upgrade, Glamsterdam, will be implemented sometime in 2026 and include improvements expected to lower the cost of using Ethereum mainnet.

Aleks Gilbert is DL News’ New York-based DeFi correspondent. You can reach him at aleks@dlnews.com.