Ethereum’s Fusaka Hard Fork Activates PeerDAS — Up to 8× L2 Throughput, Lower Fees

Ethereum activated the Fusaka hard fork on Dec 3, 2025, introducing Peer Data Availability Sampling (PeerDAS) and several blob-parameter tweaks to boost data availability and throughput for Layer‑2 rollups. PeerDAS lets validators verify small random samples instead of full blocks, cutting node bandwidth needs by roughly 80–85% and enabling up to an ~8× increase in L2 data throughput as rollups adopt the change. Fusaka also adjusts blob parameters (via Blob Parameter Only forks), raises the block gas limit from 30M to 150M gas, and implements EIP‑7825 (a per-transaction gas cap ~16.78M gas) to prevent single transactions from exhausting blocks. The rollout is staged: Fusaka activated Dec 3 then begins incremental blob-cap increases (first parameter bump shortly after activation), with a second BPO fork scheduled in early January to lift blobs-per-block further (to 14 blobs per block in the final step). Expected near-term effects include materially lower Layer‑2 transaction fees (estimates ~40–60% reductions depending on rollup adoption and network demand) and cheaper blob fees for rollups. Major L2s (Arbitrum, Optimism, Base) are expected to integrate PeerDAS in the coming weeks, which should increase on‑chain settlement capacity and reduce resource costs for rollups. Fusaka follows the Pectra upgrade earlier in 2025 and fits Ethereum’s modular roadmap toward Osaka (2026), which will add blob streaming and stateless validator client features. For traders: the upgrade reduces L2 operational costs and improves scaling headroom — monitor rollup integrations, blob-fee dynamics, and gas-market responses for short‑term volatility and fee‑sensitivity in ETH and L2 tokens.