Ethereum’s Fusaka Update: Enhancing Core Layer Scalability to Integrate Layer 2 Solutions

Ethereum’s Fusaka upgrade, a significant hard fork designed to boost both scalability and data availability, is scheduled to go live on the mainnet on December 3, 2025, after a gradual rollout on multiple testnets. This upgrade will double the number of blobs per block from the current 6/9 to 14/21 by way of two Blob Parameter Only (BPO) forks, set for December 17 and January 7, 2026. Increasing blob capacity is expected to lower transaction fees and increase throughput for Layer 2 (L2) rollups, which depend on off-chain data storage to expand Ethereum’s capabilities title1 [ 1 ].

The Fusaka upgrade includes 11–12

Improvement Proposals (EIPs), with the main improvements focused on backend systems rather than direct user features. A major highlight is PeerDAS (Peer Data Availability Sampling), introduced by EIP-7594, which enables validator nodes to check data by sampling smaller portions of blob data instead of downloading full blocks. This approach reduces both bandwidth and storage needs while keeping security intact, making L2 adoption more efficient title1 [ 1 ]. The upgrade will also implement capped base fees for blob transactions (EIP-7918) to help control costs for data-intensive applications and strengthen resistance against spam to help defend against network attacks title1 [ 1 ].

The phased rollout begins with Holesky testnet on October 1, continues with Sepolia on October 14, and then Hoodi on October 28. Each testnet will verify the BPO fork sequence, which automatically increases blob capacity without manual adjustments. This staggered deployment lets developers observe results and resolve any issues before the mainnet launch title1 [ 1 ]. Deadlines for node operators to prepare their infrastructure range from September 25 (Holesky) to November 3 (mainnet), ensuring everything is set in time title1 [ 1 ].

This upgrade addresses the urgent need to scale Ethereum’s foundational layer, especially amid concerns over L2 fragmentation. While L2 solutions have improved throughput, they have also led to isolated chains with limited connectivity. Fusaka’s backend enhancements are intended to expand base layer capacity while enabling continued expansion of L2 solutions. Recent delays in the validator exit queue—exceeding 43 days—underscore the network’s scalability issues, though Vitalik Buterin has argued these measures are crucial for security title2 [ 2 ].

Looking further ahead, proposals like EIP-7935 suggest raising the gas limit from 45 million to 150 million, while EIP-9698 outlines a 100-fold gas limit increase over two years, potentially allowing Ethereum to reach 2,000 transactions per second. These advances align with broader industry movements, such as the Open Intents Framework, aimed at improving cross-chain compatibility and addressing the $21 billion problem of multichain crime title1 [ 1 ].

The Ethereum Foundation’s plan emphasizes incremental, non-disruptive scaling improvements, such as cell-level messaging and pipelining, to make bandwidth usage more efficient. Upcoming upgrades, including PeerDAS v2 and research into FullDAS, are expected to further increase data availability throughput while maintaining decentralization. With these efforts, Ethereum aims to rival high-performance blockchains like

, which has drawn institutional attention with initiatives like Solmate, a $300 million digital asset treasury that focuses on staking and infrastructure title6 [ 6 ].