Vitalik Buterin calls the Fusaka upgrade extremely important: PeerDAS drops storage requirements by 90%, significantly reducing network limitations.

Ethereum will launch the Fusaka upgrade in December, with Vitalik emphasizing “security first”. The core technology PeerDAS is expected to significantly reduce the burden on nodes and accelerate L2. This article analyzes the key impacts and challenges. (Background: Tom Lee expresses confidence: Ethereum is the “truly neutral blockchain” and is expected to reach 12,000 by the end of the year, while Bitcoin aims for 250,000 USD) (Background supplement: Analysts under Tom Lee: Ethereum's 4000 USD defense battle, stabilizing the long-term attack on 5500 USD) There are just over two months left until Ethereum's anticipated Fusaka upgrade, set to launch on December 3, 2025. Founder Vitalik Buterin posted on X on September 24, reiterating the “security first” principle. The core upgrade, PeerDAS (Peer Data Availability Sampling), is seen as key to solving the scalability and security range-bound issue, garnering significant market attention. Vitalik's “security first”: Fusaka strategy positioning Vitalik pointed out in his post that Fusaka will initially go online with a conservative amount of blobs, observing network feedback gradually. He stated: “Security always comes first; we would rather be slower than sacrifice stability.” Over the past two years, the development team has focused on reducing the load on individual nodes while maintaining blockchain integrity. Vitalik believes that the introduction of PeerDAS makes it possible to “not download complete data,” which is crucial for the operational costs of nodes and the degree of decentralization. There are two scenarios where complete block data still needs to be stored centrally: (i) initial broadcast; (ii) reconstruction, to prevent publishers from releasing 50% <= p < 100% of the block. However, these roles are untrustworthy: we only need one honest participant to perform these operations; if there are 100 dishonest participants simultaneously, the protocol will bypass them directly. Different nodes can perform this task for different blocks. Exploring PeerDAS: A New Way of Data Availability PeerDAS allows nodes to check only a small portion of blob data through random sampling and erasure coding mechanisms, enabling them to prove the overall data availability with high probability: Random sampling: Each node only needs to download about 1/8 of the blob data to make a credible judgment on over 50% availability. Erasure coding redundancy: Even if part of the block is missing, the complete content can be restored through redundant coding, ensuring that users can ultimately read the same data. Decentralized verification: The process does not require trusting a single participant; as long as there is one honest node, the entire system can exclude malicious behavior. According to the development team's estimates, the bandwidth and storage requirements for validators are expected to decrease by 80-90%; light clients can thus participate in more complex verification tasks, significantly lowering the network threshold. The Chain Reaction Effect on L2 and Future L1 PeerDAS not only improves the on-chain experience but is also seen as a “turning point” in Ethereum's long-term scalability roadmap. First, for Rollups like Arbitrum and Optimism, larger blob capacity and lower calldata costs can directly increase the number of transactions per second and lower fees. EIP-7918 also proposes predictable, limited blob base costs, combined with the BPO (Blob Parameter Only) fork, to minimize fee fluctuations. The long-term significance lies in L1. This upgrade lays the foundation for data availability required for Danksharding, with officials estimating that the final TPS limit could increase from the current approximately 30 to a theoretical value of 12,000. As the Gas limit and on-chain data volume expand simultaneously, PeerDAS is seen as an important safety net to avoid centralization and security discounts. Challenges, Timeline, and Market Expectations Technological progress comes with risks. Vitalik repeatedly reminds the community that the complexity and testing scope of PeerDAS are higher than previous upgrade phases, hence adopting a “gradual opening” strategy: Phase One: At launch, only a small number of blobs will be allowed, prioritizing the testing of network connectivity and reconstruction processes for stability. Phase Two: Adjust the blob limit based on on-chain indicators and client error rates, while expanding the types of participating nodes. Final Phase: Only when data remains stable will considerations be made to increase L1 Gas and Rollup penetration rates. The market holds high hopes for this upgrade. If it lands successfully, Rollup transaction fees could further decrease, providing DeFi and gaming DApps with broader operational space. For developers, there will be no need to make stark trade-offs between speed and decentralization. Returning to Vitalik's principle—security comes first. Fusaka reflects Ethereum's consistent conservative and steady path: first ensuring base availability, then gradually increasing performance. As December approaches, the community is holding its breath for this critical run to overcome the data availability bottleneck. Related reports: Is Ethereum facing a staking bottleneck? DAT, staking ETFs, and chain reactions of optimism Vitalik's new article: Low-risk DeFi for Ethereum is like search for Google Ethereum “generating power with love”: Developers' salaries are only 50% of the industry average; are they staying due to a sense of mission? <Vitalik calls Fusaka upgrade super important: PeerDAS reduces storage needs by 90%, significantly lowering network restrictions> This article was first published in BlockTempo, the most influential blockchain news media.