Fusaka exposes bottlenecks after upgrade? The high failure rate of Ethereum's Blob blocks soars, and Layer 2 scalability faces a test

January 27 News, a recent analysis disclosed by blockchain research organization MigaLabs shows that after the Ethereum Fusaka upgrade was completed in December 2025, there was a significant pressure when processing data-intensive blocks. This raises questions about whether it can support larger-scale Layer 2 data throughput. The core goal of the Fusaka hard fork is to allow Layer 2 networks to submit more blob data to the mainnet, thereby reducing Rollup costs and increasing scalability, but actual operation has not fully met expectations.

Based on data from over 750,000 block slots since October 2025, MigaLabs found that although the official target for blobs per block has gradually increased to 14, the median number of blobs in the network has actually decreased. Blocks containing 16 or more blobs are extremely rare, occurring only a few hundred times, indicating that the expanded capacity is far from being fully utilized.

More concerning is that as the number of blobs increases, the probability of blocks being missed by the network rises significantly. Data shows that with up to 15 blobs, the miss rate is about 0.5%; once it reaches 16 or more, this rate jumps to between 0.77% and 1.79%. In the highest observed case of 21 blobs, the failure rate is more than three times the network average. Such high-data blocks mainly come from large Layer 2 networks like Arbitrum and Base, which heavily rely on Ethereum’s data availability to maintain their security.

If future Layer 2 activity continues to heat up and high-blob blocks become more frequent, this compounded failure rate could put pressure on Ethereum’s overall stability. Based on this trend, MigaLabs recommends delaying further increases in blob capacity until the failure rate of high-data blocks drops back to baseline levels and real demand approaches the current upper limit.

Meanwhile, the Ethereum Foundation is also planning for long-term security. Researcher Justin Drake has announced the launch of a post-quantum encryption project, led by Thomas Coratger and Emile, with an investment of $2 million. This indicates that Ethereum is facing more refined technical trade-offs between scalability and security.