Ethereum Fusaka hard fork activated, PeerDAS leads Layer 2 scaling into a new phase

In the early hours of December 4, Beijing time, Ethereum successfully activated a hard fork upgrade named “Fusaka,” marking the network’s second major code change in 2025. The core of this upgrade is the introduction of the PeerDAS system, designed to significantly reduce node operation costs and accelerate Layer 2 network settlement efficiency by allowing validators to verify only sampled portions of data. Fusaka, which includes 13 Ethereum Improvement Proposals (EIPs), signifies a solid and pragmatic step for Ethereum in addressing the growing burden of Layer 2 data and optimizing network scalability.

Fusaka Upgrade Successfully Activated: A Swift and Pragmatic Update

Ethereum underwent a key evolution in a calm manner. On December 3 at 21:49 (UTC), the hard fork codenamed “Fusaka” was activated as scheduled, and about 15 minutes later, it was successfully finalized, with the entire process unfolding smoothly. Community members, including core developers from the Ethereum Foundation, witnessed and celebrated the moment together via EthStaker livestream. The name Fusaka is a fusion of “Fulu” and “Osaka,” representing a dual upgrade of both the consensus layer (responsible for transaction validation and finalization) and the execution layer (which runs smart contracts and processes transactions).

The speed of this upgrade has been seen by outsiders as a strong response from the Ethereum development team to its reputation for “slow upgrades.” The team adopted a pragmatic strategy: prioritizing the deployment of the crucial yet manageable PeerDAS improvement, while postponing features that require deeper research or are too complex and might delay the upgrade. As Consensys engineer and Ethereum core developer Gabriel Trintinalia put it, this prioritization “truly shows that Ethereum is serious about improving mainnet speed.” Fidelity Digital Assets also noted in a recent report that Fusaka is a decisive step for Ethereum toward a more strategically coordinated and economically coherent roadmap.

The successful activation of Fusaka is not only a technical iteration but also a positive signal. It shows that Ethereum has found a balance between “big visions” (like sharding) and “incremental improvements,” enabling a more agile response to the ecosystem’s urgent needs, especially data pressure from Layer 2 scaling solutions. This efficient execution is crucial for maintaining Ethereum’s leading position among smart contract platforms.

The Core Powerhouse: How PeerDAS Eases the Burden for Validators and Layer 2?

The heart of the Fusaka upgrade is PeerDAS. This somewhat tongue-twisting technology stands for “Peer Data Availability Sampling,” and it directly targets the current efficiency bottleneck in Layer 2 data submission mechanisms. Put simply, it changes how validators verify data, moving from “full data checking” to “sampling checks,” thereby reducing costs and increasing efficiency.

Before PeerDAS was deployed, each Layer 2 network would package transaction data into a complete “blob” and submit it to the Ethereum mainnet, and every validator node had to download and verify the entire blob for completeness. This process consumed a lot of bandwidth and computing resources, and was one of the causes of network congestion and gas fee fluctuations. With PeerDAS, validators no longer need to download the entire blob, but only randomly sample and verify a small portion. As long as enough validators perform their respective sampling checks, the entire blob can be guaranteed to be available and correct with a very high probability.

This change brings dual benefits. For the vast Layer 2 ecosystem, the data submission and verification process becomes faster and cheaper, helping to further reduce transaction fees for Layer 2 users and improve the network’s overall throughput. For validators—especially individuals or small operators running single or few validator nodes—the hardware and bandwidth requirements drop significantly, which is beneficial for network decentralization. Of course, for institutional node operators like large staking pools, the marginal cost savings may be less noticeable. Ethereum Foundation core developer Marius Van Der Wijden cautions that the effects of the upgrade will take months to fully materialize, and the team will gradually increase the number of blobs to ensure network security.

Fusaka Upgrade Key Data and EIP Overview

Upgrade Time: December 4, 2024, 21:49 (UTC) activation, finalized about 15 minutes later.

Core Feature: Introduction of the PeerDAS (Peer Data Availability Sampling) system.

Included Proposals: A total of 13 Ethereum Improvement Proposals, primarily focusing on network optimization and developer experience in addition to PeerDAS.

Key EIP Examples:

• EIP-7935: Raises the default block gas limit from 30 million to 60 million, allowing each block to accommodate more computation.
• EIP-7910: Adds new API methods for software to query node configuration rules.
• EIP-7918: Ensures that blob fees align with actual processing costs, preventing extreme price volatility.
• EIP-7951: Adds native support for widely used cryptographic signature types.

More Than PeerDAS: A Bundle of Upgrades for Network Health

While PeerDAS shines, the Fusaka upgrade is not a “single-point breakthrough” but rather a “combo” of 13 Ethereum Improvement Proposals. These proposals mostly aim to optimize the developer experience and maintain the network’s long-term health, showcasing Ethereum’s meticulous engineering mindset in governance.

For example, EIP-7642 removes obsolete and unused fields from Ethereum network messages, “slimming down” the protocol; EIP-7823 and EIP-7825 respectively set limits on specific mathematical operations and single transaction sizes to prevent malicious or abnormal operations from over-consuming network resources; EIP-7883 adjusts gas costs to make certain heavy computational operations more accurately reflect their actual resource consumption, ensuring economic fairness. These improvements are like precision tune-ups for the network engine—though not strongly felt by most users, they significantly enhance system stability and resilience.

Additionally, some proposals pave the way for future upgrades. EIP-7892 will allow future adjustments only to blob-related parameters without touching the entire protocol, making optimizations safer and easier. EIP-7917 makes the block proposer’s prediction process more transparent and reliable, enhancing the predictability of the consensus mechanism. These combined improvements bolster Ethereum’s base infrastructure, preparing it for the future flood of Layer 2 data with stronger capacity and higher operational efficiency.

Market Impact and Outlook: Ethereum’s Path to Quality and Efficiency

The market significance of the Fusaka upgrade is that it does not pursue unrealistic throughput surges, but focuses on solving the most practical and urgent bottleneck: lowering data availability costs. For the entire Ethereum ecosystem, especially the booming Layer 2 sector, this is a timely boost. Lower settlement costs mean Layer 2 networks can offer users more competitive fees and support more complex and high-frequency applications, further cementing Ethereum’s core value as a “settlement layer.”

From an investment perspective, this upgrade further strengthens the narrative of Ethereum as the “infrastructure of the crypto world.” By continually lowering participation thresholds (node operation) and usage costs (Layer 2 transactions), Ethereum is expanding its potential user and developer base. Attention and positive evaluations from traditional financial institutions like Fidelity also reflect mainstream capital’s recognition of Ethereum’s pragmatic development path. In the short term, the upgrade’s effects will take time to permeate and are unlikely to trigger drastic price swings; but in the medium to long term, it is undoubtedly a key step in improving the network’s fundamentals and appeal.

Looking ahead, Ethereum developers are not slowing down. After Fusaka, the next major upgrade, “Glamsterdam,” is already on the discussion agenda, though its specific content and timeline remain undetermined. It is foreseeable that Ethereum’s upgrade roadmap will continue to deepen along the paths of “modularity” and “rollup-centricity”—enhancing mainnet security and data availability guarantees while letting Layer 2s flourish with execution layer scalability innovations. The success of Fusaka is a promising start for this long journey that requires both grand vision and solid engineering.

PeerDAS Technical Principle Explained and Recent Ethereum Upgrade History

How does PeerDAS work? A Simple Analogy

Imagine Ethereum as a giant distributed library, with each “blob” submitted by Layer 2 like a new book. Previously, every librarian (validator) had to read the entire book to confirm its contents, which was time-consuming and labor-intensive. After PeerDAS, librarians no longer need to read the whole book but instead randomly check a few pages (data samples). If enough librarians each randomly inspect different pages and none find problems, they can be highly confident that the book as a whole is sound. This method uses probabilistic assurance instead of deterministic full inspection, greatly improving efficiency without compromising security.

A Brief History of Recent Ethereum Upgrades (2023-2025)

1. Shanghai Upgrade (April 2023): Allowed withdrawals of staked ETH, completing Ethereum’s transition to Proof of Stake and greatly boosting staking confidence.
2. Cancun-Denver Upgrade (March 2024): Introduced Proto-Danksharding (EIP-4844), significantly lowering data publishing costs for Layer 2 via “blobs,” a milestone for Layer 2 development.
3. Prague Upgrade (Mid-2025): Mainly introduced early support for Verkle trees, paving the way for stateless clients and further improving node scalability.
4. Fusaka Upgrade (December 2025): The current upgrade, centered on PeerDAS, aims to optimize data availability sampling, further reducing Layer 2 costs and validator burdens.

With the dust settled on the Fusaka upgrade, there was no earth-shaking price volatility, but Ethereum’s “underground infrastructure” has undergone a crucial expansion. It may not be as dazzling as a skyscraper’s completion, yet it determines how many residents and applications the city can support in the future. While market attention is often drawn to flashy narratives, Ethereum keeps its head down, laying a solid foundation. PeerDAS and its dozen-plus accompanying optimizations embody this pragmatic spirit: not chasing overnight miracles, but tackling the next most specific and urgent bottleneck. In the blockchain world, the fastest upgrade may not always be the best; those carefully crafted improvements that pave the road for the next decade are often the true bedrock of the next bull cycle. After Fusaka, perhaps the better question is: what new wave of applications will a more efficient and accessible Ethereum bring forth?