Ethereum's Fusaka Upgrade Aims to Solve Scaling Trilemma

Vitalik Buterin, co-founder of Ethereum, has emphasized the pivotal role of the Fusaka upgrade in addressing the network’s scaling challenges. Scheduled for activation on December 3, 2025, the hard fork introduces PeerDAS (Peer Data Availability Sampling), a system designed to enhance Ethereum’s scalability by enabling nodes to verify data availability without downloading full datasets. This innovation, outlined in Ethereum Improvement Proposal (EIP) 7594, allows nodes to sample smaller data chunks and reconstruct the complete dataset using erasure coding, reducing congestion while preserving security and decentralizationVitalik Buterin: Fusaka Will Fix Ethereum Scaling With PeerDAS^[1]. Buterin described the approach as “pretty unprecedented,” highlighting its potential to resolve the long-standing trilemma of balancing security, scalability, and decentralizationVitalik Buterin says Fusaka upgrade's PeerDAS is key to Ethereum^[2].

The upgrade builds on the Dencun upgrade, which introduced blobs—temporary data containers for rollups—to lower transaction costs on Layer 2 (L2) solutions. Fusaka doubles the blob capacity from 6/9 to 14/21 per block through incremental Blob Parameter Only (BPO) forks, with initial conservative increases planned for January 2026Ethereum’s Fusaka Upgrade: A Game-Changer for Businesses and^[3]. This expansion is expected to reduce L2 transaction fees to below $0.1, enabling use cases like micropayments, consumer applications, and AI-driven toolsVitalik Buterin: Fusaka Will Fix Ethereum Scaling With PeerDAS^[4]. Developers also anticipate faster withdrawals and improved cross-rollup aggregation, fostering a unified “Ethereum superchain” ecosystemEthereum’s Fusaka Upgrade: What the November 2025 Hard^[5].

Buterin underscored the cautious rollout of blob capacity increases, stressing the importance of thorough testing to ensure network stability. While blob counts will rise incrementally, the long-term goal is to extend PeerDAS to Ethereum’s base layer, potentially moving L1 execution data into blobs to further reduce node strainVitalik Buterin says Fusaka upgrade's PeerDAS is key to Ethereum^[6]. This phased approach aligns with Ethereum’s broader strategy to scale transaction throughput while maintaining decentralization, with projections suggesting Layer 1 capacity could eventually surpass 150 million gas per blockEthereum’s Fusaka Upgrade: What the November 2025 Hard^[7].

The Fusaka upgrade is part of Ethereum’s rollup-centric roadmap, with developers prioritizing scalability over immediate user-facing features. The hard fork bundles 11 Ethereum Improvement Proposals (EIPs), including spam resistance checks, gas cost adjustments, and optimizations for validator operationsEthereum Fusaka Upgrade: What It Means for ETH^[8]. Testnets on Holesky, Sepolia, and Hoodi were successfully deployed in late 2025, with the mainnet activation coordinated to precede the Devconnect conference in Buenos AiresEthereum’s Fusaka Upgrade: What the November 2025 Hard^[9].

Analysts suggest the upgrade could strengthen Ethereum’s role as the backbone of decentralized finance (DeFi), with $132 billion in deposits already locked on the network. By lowering L2 costs and increasing data availability, Fusaka positions Ethereum to compete with high-throughput chains while retaining its decentralized security modelEthereum Fusaka Upgrade: What We Know So Far?^[10]. Buterin envisions a future where Ethereum’s L2 ecosystem and base layer achieve “truly mainstream” adoption, enabling billions of users to access low-risk DeFi applicationsVitalik Buterin: Fusaka Will Fix Ethereum Scaling With PeerDAS^[11].