Ethereum's Fusaka Upgrade Activates Successfully

Ethereum's Fusaka upgrade activated successfully on December 4, 2025, marking a significant advancement in the blockchain's scalability and data handling capabilities with no network downtime. The hard fork, which builds on prior enhancements like the 2022 Merge and the Dencun upgrade, introduces mechanisms to expand data availability for layer-2 rollups while maintaining security and decentralization.

The upgrade's centerpiece is PeerDAS, a data availability sampling system that allows nodes to verify large volumes of transaction data by checking small, random samples rather than downloading entire payloads. This reduces bandwidth and storage demands on validators, enabling up to eightfold increases in throughput for rollups such as Arbitrum, Optimism, and Base. Previously, these networks batched transactions and posted compressed data as blobs to Ethereum's main chain, but limited blob space often led to fee spikes during high demand. Fusaka addresses this through the Blob Parameter Only (BPO) mechanism, which permits flexible adjustments to blob capacity without requiring full hard forks. Initially maintaining a target of six blobs per block, the system schedules increases...