Ethereum activated the Fusaka improve on Dec. 3, 2025, elevating the community’s knowledge availability capability by Blob Parameter Overrides that incrementally expanded blob targets and maximums.
Two subsequent changes raised the goal from 6 blobs per block to 10, then to 14, with a most ceiling of 21. The aim was to scale back layer-2 rollup prices by growing throughput for blob knowledge, the compressed transaction bundles that rollups submit to Ethereum for safety and finality.
Three months into knowledge assortment, the outcomes reveal a spot between capability and utilization. A MigaLabs evaluation of over 750,000 slots since Fusaka’s activation exhibits that the community isn’t reaching the target blob count of 14.
Median blob utilization really declined after the primary parameter adjustment, and blocks containing 16 or extra blobs exhibit elevated miss charges, suggesting reliability degradation on the edges of latest capability.
The report’s conclusion is direct: no additional will increase within the blob parameter till high-blob miss charges normalize and demand materializes for the headroom already created.
What Fusaka modified and when it occurred
Ethereum’s pre-Fusaka baseline, established through EIP-7691, set the goal at 6 blobs per block with a most of 9. The Fusaka improve launched two sequential Blob Parameter Override changes.
The first was activated Dec. 9, elevating the goal to 10 and the utmost to fifteen. The second was activated Jan. 7, 2026, pushing the goal to 14 and the utmost to 21.
These adjustments did not require arduous forks, and the mechanism permits Ethereum to dial capability by shopper coordination moderately than protocol-level upgrades.
The MigaLabs evaluation, which printed reproducible code and methodology, tracked blob utilization and community efficiency throughout this transition.
It discovered that the median blob rely per block fell from 6 earlier than the primary override to 4 afterward, regardless of the community’s capability increasing. Blocks containing 16 or extra blobs stay extraordinarily uncommon, occurring between 165 and 259 instances every throughout the statement window, relying on the precise blob rely.
The community has headroom it is not utilizing.
One parameter discrepancy: the report’s timeline textual content describes the primary override as elevating the goal from 6 to 12, however the Ethereum Foundation’s mainnet announcement and shopper documentation describe the adjustment as 6 to 10.
We use the Ethereum Foundation’s parameters as source: 6/9 baseline, 10/15 after the primary override, 14/21 after the second. However, we deal with the report’s dataset for noticed utilization and miss-rate patterns because the empirical spine.
Miss charges climb at excessive blob counts
Community reliability measured by missed slots, that are blocks that fail to propagate or attest accurately, exhibits a transparent sample.
At decrease blob counts, the baseline miss charge sits round 0.5%. As soon as blocks attain 16 or extra blobs, miss charges climb to 0.77% to 1.79%. At 21 blobs, the utmost capability launched within the second override, the miss charge hits 1.79%, greater than triple the baseline.
The evaluation breaks this down throughout blob counts from 10 to 21, displaying a gradual degradation curve that accelerates previous the 14-blob goal.
This degradation issues as a result of it suggests the community’s infrastructure, resembling validator hardware, community bandwidth, and attestation timing, struggles to deal with blocks on the higher finish of capability.
If demand ultimately rises to fill the 14-blob goal or push towards the 21-blob most, the elevated miss charges may translate into significant finality delays or reorg threat. The report frames this as a stability boundary: the community can technically course of high-blob blocks, however doing so persistently and reliably stays an open query.
Blob economics: why the reserve worth flooring issues
Fusaka did not solely increase capability. It additionally modified blob pricing by EIP-7918, which introduces a reserve worth flooring to forestall blob auctions from collapsing to 1 wei.
Earlier than this transformation, when execution prices dominated and blob demand stayed low, the blob base price may spiral downward till it successfully disappeared as a worth sign. Layer-2 rollups pay blob charges to submit their transaction knowledge to Ethereum, and people charges are presupposed to replicate the computational and community prices that blobs impose.
When charges fall to close zero, the financial suggestions loop breaks, and rollups eat capability with out paying in proportion. This ends in the community shedding visibility into precise demand.
EIP-7918’s reserve worth flooring ties blob charges to execution prices, guaranteeing that even when demand is delicate, the worth stays a significant sign.
This prevents the free-rider drawback the place low-cost blobs encourage wasteful utilization and supplies clearer knowledge for future capability selections: if blob charges keep elevated regardless of elevated capability, demand is real; in the event that they collapse to the ground, headroom exists.
Early knowledge from Hildobby’s Dune dashboard, monitoring Ethereum blobs, exhibits that blob charges have stabilized after Fusaka moderately than persevering with the downward spiral seen in earlier intervals.
The typical blob rely per block confirms MigaLabs’ discovering that utilization hasn’t surged to fill the brand new capability. Blocks routinely carry fewer than the 14-blob goal, and the distribution stays closely skewed towards decrease counts.
What the information reveals about effectiveness
Fusaka succeeded in increasing technical capability and proving the Blob Parameter Override mechanism works with out requiring contentious arduous forks.
The reserve worth flooring seems to be functioning as supposed, stopping blob charges from turning into economically meaningless. However utilization lags behind capability, and reliability on the edges of latest capability exhibits measurable degradation.
The miss charge curve suggests Ethereum’s present infrastructure comfortably handles the pre-Fusaka baseline and the primary override’s 10/15 parameters, however begins to pressure previous 16 blobs.
This creates a threat profile: if layer-2 exercise surges and pushes blocks towards the 21-blob most recurrently, the community may face elevated miss charges that compromise finality and reorg resistance.
Demand patterns supply one other sign. Median blob utilization falling after the primary override, regardless of elevated capability, means that layer-2 rollups aren’t at present constrained by blob availability.
Both their transaction volumes have not grown sufficient to require extra blobs per block, or they’re optimizing compression and batching to suit inside present capability moderately than increasing utilization.
Blobscan, a devoted blob explorer, exhibits particular person rollups posting comparatively constant blob counts over time moderately than ramping as much as exploit new headroom.
The pre-Fusaka concern was that restricted blob capability would bottleneck Layer 2 scaling and preserve rollup charges elevated as networks competed for scarce knowledge availability. Fusaka addressed the capability constraint, however the bottleneck seems to have shifted.
Rollups aren’t filling the accessible area, which implies both demand hasn’t arrived but or different components, resembling sequencer economics, consumer exercise, and cross-rollup fragmentation, are limiting development greater than blob availability was.
What comes subsequent
Ethereum’s roadmap consists of PeerDAS, a extra basic redesign of knowledge availability sampling that may additional increase blob capability whereas enhancing decentralization and safety properties.
Nonetheless, the Fusaka outcomes recommend that uncooked capability is not the binding constraint proper now.
The community has room to develop into the 14/21 parameters earlier than needing one other enlargement, and the reliability curve at excessive blob counts signifies that infrastructure upgrades might must catch up earlier than capability will increase once more.
The miss charge knowledge supplies a transparent boundary situation. If Ethereum pushes capability greater whereas 16+ blob blocks nonetheless present elevated miss charges, it dangers introducing systemic instability that might floor throughout high-demand intervals.
The safer path is to let utilization rise towards the present goal, monitor whether or not miss charges enhance as shoppers optimize for greater blob masses, and modify parameters solely as soon as the community demonstrates it might probably reliably deal with edge instances.
Fusaka’s effectiveness will depend on the metric. It expanded capability efficiently and stabilized blob pricing by the reserve flooring. It did not drive quick utilization will increase or clear up the reliability challenges at most capability.
The improve created headroom for future development, however whether or not that development materializes stays an open query the information hasn’t answered but.
