Ethereum is rolling out the Fusaka hard fork today, an upgrade aimed at significantly improving data availability and scaling across the network. This is the blockchain’s second major upgrade of 2025, following the earlier Pectra hard fork.Key Data and Performance Enhancements Scheduled for activation at 21:49 UTC, Fusaka introduces Peer Data Availability Sampling (PeerDAS), a feature that lets validators check only small, randomly chosen pieces of block data instead of downloading full blocks. This approach cuts bandwidth demands by up to 85% and can boost data throughput for Layer 2 rollups by as much as 8x.To make this possible, the upgrade includes Blob Parameter Only (BPO) forks, which adjust settings such as blob targets, blob maximums, and fee update fractions.Additionally, the hard fork increases Ethereum’s block gas limit from 30 million to 150 million, allowing far more transactions per block. Layer 2 networks are expected to benefit the most, with projected fee reductions of 40–60%, depending on network congestion and how quickly rollups adopt the new changes.