Ethereum activated the Fusaka improve on Dec. 3, 2025, elevating the community’s information 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 cut back layer-2 rollup prices by growing throughput for blob information, the compressed transaction bundles that rollups publish to Ethereum for safety and finality.
Three months into information assortment, the outcomes reveal a niche between capability and utilization. A MigaLabs evaluation of over 750,000 slots since Fusaka’s activation exhibits that the community is not reaching the goal blob rely 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 by 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 primary 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 modifications did not require laborious forks, and the mechanism permits Ethereum to dial capability by shopper coordination reasonably 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 Basis’s mainnet announcement and shopper documentation describe the adjustment as 6 to 10.
We use the Ethereum Basis’s parameters as supply: 6/9 baseline, 10/15 after the primary override, 14/21 after the second. Nonetheless, 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, exhibiting a gradual degradation curve that accelerates previous the 14-blob goal.
This degradation issues as a result of it suggests the community’s infrastructure, reminiscent of validator {hardware}, community bandwidth, and attestation timing, struggles to deal with blocks on the higher finish of capability.
If demand finally rises to fill the 14-blob goal or push towards the 21-blob most, the elevated miss charges might translate into significant finality delays or reorg danger. The report frames this as a stability boundary: the community can technically course of high-blob blocks, however doing so constantly and reliably stays an open query.
Blob economics: why the reserve worth ground issues
Fusaka did not solely broaden capability. It additionally modified blob pricing by EIP-7918, which introduces a reserve worth ground to stop blob auctions from collapsing to 1 wei.
Earlier than this transformation, when execution prices dominated and blob demand stayed low, the blob base charge might spiral downward till it successfully disappeared as a worth sign. Layer-2 rollups pay blob charges to publish their transaction information to Ethereum, and people charges are speculated 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 leads to the community shedding visibility into precise demand.
EIP-7918’s reserve worth ground ties blob charges to execution prices, guaranteeing that even when demand is smooth, the worth stays a significant sign.
This prevents the free-rider downside the place low-cost blobs encourage wasteful utilization and supplies clearer information 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 information from Hildobby’s Dune dashboard, monitoring Ethereum blobs, exhibits that blob charges have stabilized after Fusaka reasonably 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 info reveals about effectiveness
Fusaka succeeded in increasing technical capability and proving the Blob Parameter Override mechanism works with out requiring contentious laborious forks.
The reserve worth ground seems to be functioning as meant, stopping blob charges from changing 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 danger profile: if layer-2 exercise surges and pushes blocks towards the 21-blob most usually, the community might face elevated miss charges that compromise finality and reorg resistance.
Demand patterns provide one other sign. Median blob utilization falling after the primary override, regardless of elevated capability, means that layer-2 rollups aren’t presently 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 reasonably than increasing utilization.
Blobscan, a devoted blob explorer, exhibits particular person rollups posting comparatively constant blob counts over time reasonably than ramping as much as exploit new headroom.
The pre-Fusaka concern was that restricted blob capability would bottleneck Layer 2 scaling and hold rollup charges elevated as networks competed for scarce information availability. Fusaka addressed the capability constraint, however the bottleneck seems to have shifted.
Rollups aren’t filling the obtainable area, which implies both demand hasn’t arrived but or different components, reminiscent of sequencer economics, consumer exercise, and cross-rollup fragmentation, are limiting development greater than blob availability was.
What comes subsequent
Ethereum’s roadmap contains PeerDAS, a extra basic redesign of knowledge availability sampling that may additional broaden blob capability whereas bettering decentralization and safety properties.
Nevertheless, 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 growth, 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 information supplies a transparent boundary situation. If Ethereum pushes capability larger 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 larger blob hundreds, and regulate parameters solely as soon as the community demonstrates it could possibly reliably deal with edge circumstances.
Fusaka’s effectiveness depends upon the metric. It expanded capability efficiently and stabilized blob pricing by the reserve ground. It did not drive instant utilization will increase or resolve 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 info hasn’t answered but.
