Ethereum Activates Fusaka Hard Fork, Delivering Major Data Availability and Throughput Gains

• Fusaka boosts Ethereum’s data capacity and cuts validator bandwidth use by up to 85%.
• Upgrade raises block gas limit to 150M, enabling higher throughput and lower L2 fees.
• PeerDAS adoption expected across major rollups, expanding scalability and efficiency.

Ethereum has activated its Fusaka hard fork on mainnet, marking a major move aimed at expanding data capacity and lowering costs across the network’s Layer 2 ecosystem. The upgrade, which went live at 21:49 UTC, introduces structural adjustments intended to support higher-throughput rollups, reduce bandwidth consumption for validators, and improve the chain’s ability to accommodate growing demand for block space.

At the center of the upgrade is Peer Data Availability Sampling (PeerDAS), a system enabling validators to verify randomly selected pieces of block data instead of downloading full data blobs. This modification cuts bandwidth requirements by up to 85%, allowing rollups to publish significantly more data without congesting the chain. According to network specifications, the throughput available to Layer 2 systems can now expand by as much as eight times.

Supporting these changes are Blob Parameter Only (BPO) adjustments, which tune blob targets, blob maximum limits, and fee update fractions. These parameters help manage Ethereum’s enlarged data capacity and align blob fees with expected usage patterns as rollups begin incorporating the new mechanism.

Fusaka also raises the block gas limit from 30 million to 150 million units. This creates a larger execution budget per block, enabling more transactions to be processed simultaneously. Early estimates suggest that Layer 2 networks may experience transaction fee reductions of approximately 40–60%, depending on network activity and integration timelines for each rollup.

Security and Execution Controls Strengthened by New Gas Guardrails

The upgrade includes EIP-7825, which sets a per-transaction gas cap of approximately 16.78 million gas. The cap ensures that no single transaction can consume an entire block’s execution capacity. The change reduces exposure to denial-of-service vectors while preparing the protocol for additional execution-layer improvements expected in future upgrades.

Fusaka was approved following successful activations on Hoodi, Sepolia, and Holesky testnets. The upgrade advances Ethereum’s modular roadmap, which seeks to separate execution, consensus, and data availability responsibilities for better long-term scalability. Rollup networks, including Arbitrum, Optimism, and Base are expected to enable PeerDAS support in the coming weeks.