Ethereum Fusaka is here. What exactly has this upgrade changed? A comprehensive article on the real impact on L2 and nodes

The Ethereum mainnet Fusaka fork has officially launched. This upgrade involves four core changes: PeerDAS (peer-to-peer data sampling), EIP-7918 (blob fee fix), P-256 elliptic curve precompile, and BPO (blob parameter series fine-tuning). In simple terms, it’s not a massive upgrade but a systematic optimization laying the groundwork for future scalability.

Will on-chain fees immediately become cheaper? Don’t get your hopes up

Many people hear “upgrade” and think gas fees will drop straight down. But the truth about Fusaka is: there will be no dramatic short-term changes.

In fact, gas fees had already started decreasing before Fusaka, mainly because proposers had voted to raise the L1 gas limit from 45M to 60M — this is an independent parameter change, not directly caused by Fusaka. As a result, regular transfers became slightly cheaper, but this is not closely related to the PeerDAS mechanism itself.

What does PeerDAS do? It slices blobs (Ethereum objects used to store L2 data) into 128 shards, distributing them to different nodes for storage and sampling verification, rather than each node downloading the entire blob. It sounds impressive, but a key detail is: the current maximum number of blobs per block has not increased. So, before BPO (the subsequent parameter adjustment plan) actually raises the blob limit, most users won’t notice PeerDAS’s existence.

The true scalability window will open in phases:

• First wave (mid-December): max blobs from 6 to 15, target from 9 to 10
• Second wave (early January): max blobs to 21, target to 14

By then, L2 transaction fees will see more noticeable improvements.

Blob fees from “pseudo-cheap” to “truly cheap” — this is the core value of EIP-7918

This change looks very technical but actually solves a ridiculous problem: blob fees have been stuck at 1 wei for a long time, which is equivalent to about $0.000000004 per blob.

That’s not cheap; it’s mispricing. 95% of the time, blobs cost this much, until suddenly some days they spike to 42,000 gwei — about $15,000 per blob. Such extreme volatility makes it painful for anyone trying to build serious credit markets or derivatives markets.

EIP-7918 fixes this by introducing a lower bound on blob fees tied to execution layer gas fees. Now, the blob base fee can no longer be arbitrarily close to zero but will dynamically adjust based on network congestion. What’s the result?

• Average blob fee will indeed rise (from nearly zero to about 0.025 gwei)
• Volatility will be greatly reduced
• Price curves will become predictable and manageable

The key point is: predictability, not absolute low cost. Rollup operators can now plan batch strategies based on stable price signals instead of gambling weekly whether blob prices will suddenly spike.

Redefining node operation thresholds

A subtle change brought by PeerDAS is: node roles are becoming differentiated.

Before Fusaka, full nodes either did or didn’t, and everyone downloaded roughly the same data. Now, depending on staking (stake) size, nodes bear different Data Availability (DA) responsibilities:

• Ordinary full nodes (no staking): only host 4 blob shards
• Single validator nodes (32 ETH stake): need to host 8 shards
• Multiple validator nodes: each additional 32 ETH staked adds 1 shard
• Super nodes (above 4096 ETH): host all 128 shards

The logic is: the more you stake, the greater your contribution to the network, and the higher your hardware requirements.

For Rollup projects, the most practical setup is to run a semi-super node — host 64 shards (half), then reconstruct the full blob using Reed-Solomon erasure coding. This ensures data integrity while keeping hardware costs manageable.

Will Rollups truly migrate back to Ethereum DA? The reality isn’t black and white

The extreme blob fee volatility before Fusaka did scare some projects away to alternative DA solutions (like Celestia and others). Now, the question is: Do new projects still need alt-DA?

It depends on the scenario:

• High-value DeFi, custody of large assets: Ethereum DA or well-bridged solutions. More trust assumptions = higher systemic risk.
• Gaming chains, social apps: can accept alt-DA, mainly prioritizing service availability over extreme security.
• Newly launched projects: now have a stronger reason to choose Ethereum DA — predictable costs and Ethereum’s security backing.

But projects already on alt-DA won’t all migrate back. The migration cost is too high; a more realistic long-term trend is: high-asset projects gradually move toward Ethereum DA, while low-asset projects continue with alt-DA.

Pre-confirmation arrives, but it’s not a free-for-all

Fusaka introduces the proposer lookahead mechanism, providing a reliable basis for pre-confirmation — Ethereum can pre-know the proposers for upcoming slots.

It sounds impressive, but practical application requires caution:

Single-slot pre-confirmation (most stable): the proposer commits to include your transaction in the next block, with slashing penalties for breach. This reduces confirmation time from 12-24 seconds to a few seconds.

Multi-slot pre-confirmation (experimental): can commit further into the future but without strict transaction ordering guarantees. Still under research, with risks of censorship and ordering abuse.

Based Rollup pre-confirmation: L2 relies on L1 proposer commitments, reducing confirmation time from 12-30 seconds to about 2 seconds. But beware of fair exchange issues — pre-confirmation incentivizes proposers to delay to extract extra MEV. Poor design could lead to validator mispunishments.

In practice, the most promising application of pre-confirmation is cross-chain UX improvement. Imagine users performing operations on L2 that depend on L1 liquidity; pre-confirmation can provide binding commitments before finality, making the experience feel like operating on a unified ledger.

The next 6-12 months, the real game-changers hinge on these three points

Will blob fees spiral out of control again? The key metric is price variance, not the mean. Fusaka’s success isn’t about keeping blobs at a few pennies forever but ensuring they don’t suddenly spike to sky-high prices in a single afternoon. When sampling failure rates approach the theoretical minimum, no DA failures cause finalized block issues, and nodes can keep up with chain head, then it’s a signal to safely adjust parameters.

Will actual L2 usage increase? Many Rollups haven’t pushed throughput to the limit mainly due to concerns over L1 DA costs. Now that DA is stable, Rollups should dare to accept more users and pack more transactions into blobs. If this happens, on-chain metrics will show a significant rise in unique user operations.

Will new Rollups really launch? Past delays were caused by blob volatility, uncertain DA, and decision paralysis between alt-DA and Ethereum DA. After Fusaka, the risk of Rollup deployment decisions is reduced. We expect to see more application-specific Rollups emerge, as the motivation to migrate to other ecosystems due to DA issues diminishes.

In essence, Fusaka isn’t a revolutionary upgrade in the traditional sense but a transformation: it turns Ethereum from an unreliable base layer into a dependable infrastructure layer for L2. It may seem modest, but its implications for the entire ecosystem are profound.