Ethereum's Fusaka Upgrade: Can Scalability Coexist with Decentralization?

Ethereum’s Fusaka upgrade, scheduled for activation on the mainnet in late 2025, has drawn significant attention as the blockchain community anticipates a pivotal step in scaling the network. The upgrade, part of Ethereum’s ongoing roadmap to enhance scalability and efficiency, introduces 11 Ethereum Improvement Proposals (EIPs) focused on optimizing data availability, node resilience, and transaction throughput. These changes aim to address growing demands on the network, particularly from layer 2 (L2) solutions and decentralized finance (DeFi) protocols, while maintaining decentralization and security. The Fusaka upgrade is positioned to complement recent developments, including the Pectra hard fork in May 2025, which expanded staking limits and introduced account abstraction.

A core innovation in Fusaka is , a mechanism designed to reduce the computational and storage burden on nodes. By allowing nodes to verify only a fraction of the data in each block, PeerDAS enables Ethereum to scale blob throughput—critical for L2 rollups—without requiring every node to store full data. This approach theoretically allows the network to process up to 8x more blobs per block, a key factor in reducing transaction costs and improving L2 performance. Complementing this, will allow incremental adjustments to blob limits without necessitating full network upgrades, enabling faster adaptation to evolving L2 needs.

Gas limit increases are another focal point of Fusaka. The block gas limit is set to rise from 30 million to 150 million units, a 400% increase, to accommodate higher transaction volumes. This adjustment, coupled with revised gas pricing for cryptographic operations like modular exponentiation (MODEXP), aims to prevent congestion and ensure fairer fee distribution. EIP-7918, for instance, ties blob fees to execution costs, preventing scenarios where fees spiral to negligible levels during low demand. These changes are expected to stabilize gas prices and improve predictability for users and developers.

The upgrade’s implementation is being tested through a series of public testnets, including Holesky, Sepolia, and Hoodi, with activation planned for December 3, 2025. Developers have emphasized a phased approach to minimize risks, with additional hard forks in December 2025 and January 2026 to gradually increase blob capacity from 6 to 48 blobs per block. The Ethereum Foundation has also launched a $2 million bug bounty program to incentivize security audits, underscoring the upgrade’s strategic importance.

Fusaka’s impact extends beyond technical improvements. By enhancing Ethereum’s scalability, the upgrade is expected to strengthen its competitive position against emerging blockchains like Solana and BNB Chain, which have gained traction for faster transaction speeds and lower fees. Analysts suggest that Fusaka could catalyze renewed investor interest in Ethereum, particularly as ETF approvals for Bitcoin and Ethereum gain momentum and the market seeks exposure to scalable, secure infrastructure. The upgrade also aligns with broader industry trends, including the growing adoption of L2 solutions and the expansion of DeFi, which rely on efficient data handling and low-cost transactions.

However, challenges remain. Larger blocks and higher gas limits may strain smaller validators, potentially centralizing network participation over time. Additionally, the transition to PeerDAS and BPO forks requires careful coordination among client teams to avoid fragmentation. Developers are monitoring these trade-offs closely, with further optimizations expected in the 2026 Glamsterdam upgrade, which will focus on reducing block times and integrating advanced EVM features.

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[2] Ethereum: Fusaka update expected on mainnet on December 3, … (https://en.cryptonomist.ch/2025/09/19/ethereum-fusaka-update-expected-on-mainnet-on-december-3-gas-limit-at-150m/)

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