Author: Chloe, ChainCatcher
Ethereum officially completed its major upgrade, named "Fusaka," early this morning. This is the second hard fork since the Pectra upgrade in May, symbolizing the Ethereum development team's determination to accelerate iterations and officially entering a cycle of two upgrades per year. Meanwhile, the price of ETH has climbed to a high of $3240, an increase of approximately 20% from its recent low, reflecting positive market sentiment.
The Fusaka upgrade (named a combination of Fulu and Osaka) not only encompasses comprehensive optimizations to the consensus and execution layers, but also introduces up to 12 Ethereum improvement proposals, focusing on increasing network throughput, optimizing transaction speed, and revising the economic model to strengthen ETH's deflationary mechanism.
The core highlight of this upgrade is undoubtedly the "PeerDAS (Peer Data Availability Sampling)" technology. This innovation is considered a key step in Ethereum's scaling path and is expected to reduce transaction latency from minutes to milliseconds, bringing a more immediate user experience to decentralized applications and payment systems.
Core developers witnessed the event live, demonstrating Ethereum's commitment to improving mainnet and performance.
The Fusaka upgrade proceeded smoothly and without incident, reaching final confirmation within approximately 15 minutes of being triggered at 21:49 last night. According to Coindesk, several core developers witnessed this moment during an EthStaker livestream. Consensys engineer Gabriel Trintinalia stated, "Fusaka clearly demonstrates Ethereum's commitment to improving mainnet and performance. In the early development phases of the Fusaka upgrade, any features that could potentially delay the fork, such as those requiring further research or being overly complex, were downgraded and removed from the development scope."
According to the Ethereum Foundation , the team optimistically predicts that this upgrade will lay the foundation for "instant-feel user experiences," and that the technology will unlock up to 8 times the data throughput. For L2 scaling solutions such as Optimism and Arbitrum, this is equivalent to submitting more data at a lower cost, thereby reducing transaction fees for end users, while reserving huge growth potential for the network.
PeerDAS introduces the concept of "sampling," which will unlock up to 8 times the data throughput.
As previously reported , PeerDAS was originally planned to be included in Ethereum's major upgrade to Pectra in February of this year, but was delayed due to testing requirements.
PeerDAS, short for Peer Data Availability Sampling, is a data processing mechanism designed to address the bottleneck in the Ethereum mainnet's processing of L2 commit data.
In short, since the Dencun upgrade introduced "Blob" (a temporary data storage space designed specifically for L2) in 2024, validators have had to download and verify the entire contents of each Blob, resulting in a heavy burden on network bandwidth, limited processing performance, and indirectly increased transaction fees.
According to Coin Metrics, since its introduction, Blob has seen significant adoption thanks to rollups like Base and Arbitrum. However, this has also led to Blob usage often approaching saturation (currently nearing the target of 6 Blobs per block), potentially triggering an exponential increase in rollup fees. As the demand for data availability continues to grow, Blob space has become a key bottleneck in Ethereum's scaling path.
PeerDAS's innovation lies in introducing the concept of "sampling," meaning that validators do not need to download the entire blob, but only check randomly selected "slices" (small fragments) of data. Through this peer-to-peer network sharing and verification method, the system can ensure that data availability and security are not compromised, while significantly reducing computational and storage requirements.
According to official estimates, in addition to unlocking up to 8 times the data throughput, allowing the L2 network to submit more data at a lower cost, this upgrade is expected to lower the barrier to entry for small or new validator operators by reducing the resources required to run a small number of validators. However, Ethereum developers also point out that large institutions operating a large number of nodes, such as staking pools, will not see the same savings. While the savings for large institutional validators are smaller, overall, this will make Ethereum more inclusive and attract more participants to the ecosystem.
“These improvements will take several months to fully take effect, as we will only gradually increase the number of blobs to ensure the network can safely handle the increased throughput,” said Marius Van Der Wijden, a core developer at the Ethereum Foundation.
The base price mechanism links Blob fees to L2 execution costs.
Beyond PeerDAS, the Fusaka upgrade also made precise adjustments to the economic aspects, particularly addressing the sluggish Blob fee market. Since the Dencun upgrade, due to oversupply, Blob fees have frequently fallen to an ineffective level of 1 wei, rendering the ETH burn mechanism almost ineffective in this area. According to Blockworks statistics, in the months following the Pectra upgrade, Blob fees amounted to only about $900, and even the brief peak in November was only $23,000, contributing little to the deflationary pressure on ETH.
To address this, EIP-7918 introduces a "Reserve Price" mechanism, linking Blob fees to L2 execution costs to prevent price crashes and ensure consistency with actual processing costs. This not only stabilizes market volatility but also allows Blob fees to contribute more effectively to ETH burning as L2 transaction volume grows. Combined with EIP-7892's "Blob-only hard fork" (BPO) feature, Ethereum will increase the target number of Blobs per block to 14 (maximum 21) by January 7, 2026, further expanding its capacity.
Other EIPs cover protocol cleanup and performance enhancement, such as:
EIP-7935: Increases the default block gas limit to 60 million, allowing for more computation and providing flexibility for future adjustments.
EIP-7951: Adds native support for secp256r1 (P-256) signatures, allowing wallets to integrate device biometrics and improve user login convenience.
EIP-7825 and EIP-7934: Set upper limits for transaction and block sizes to prevent resource-intensive attacks such as DoS.
EIP-7883: Improves gas costs for specific mathematical operations to ensure fair allocation of network resources.
EIP-7642: Removes outdated message fields, simplifies the protocol, and cleans up program code.
Ethereum co-founder Vitalik Buterin published an article on the X platform , pointing out that Ethereum has been continuously introducing "hard fixed rules" in recent years to improve protocol security and long-term adaptability. He recalled: EIP-2929 and EIP-3529 adjusted storage costs and reduced gas returns in 2021; Dencun upgraded and weakened contract burn instructions in 2024; and a gas cap of 16,777,216 was set for a single transaction in 2025.
Vitalik emphasized that such changes set clear processing limits, which help prevent DoS attacks, simplify clients, and expand efficiency margins. More restrictions are expected in the future, including limiting the total number of bytes of accessible program code (increasing the cost of large contracts in the short term, and adopting binary trees and billing by data block in the medium term), setting the maximum validator operation cycle and adjusting synchronization costs for zero-knowledge EVMs, and optimizing memory billing to clearly define the maximum EVM consumption limit.
Fusaka's success not only addressed current pain points but also laid the foundation for Ethereum's rapid development pace. Major upgrades, previously occurring annually (such as Shapela in 2023 and Dencun in 2024), have now been changed to semi-annually, demonstrating the Foundation's strong execution capabilities despite personnel changes.
Next year's major upgrade, "Glamsterdam" (Gloas + Amsterdam), is expected to focus on parallel processing technologies such as Block Level Access List (BAL) to further improve performance.
