The Empire Strikes Back: How Ethereum's 'Fusaka' Upgrade Redefines the Data Availability War
The Core Narrative
Fusaka — a combination of Fulu (Consensus Layer) and Osaka (Execution Layer) — is Ethereum’s most aggressive attempt to reclaim dominance in the Data Availability (DA) market.
Mainnet Target Date: December 3, 2025.
Over the past two years, Alt-DAs such as Celestia, EigenDA, and Avail gained momentum as low-cost DA solutions for rollups. Fusaka changes the equation by fundamentally increasing Ethereum’s own DA throughput and lowering its native DA cost.
PeerDAS (EIP-7594): The Game Changer
Before Fusaka, Ethereum nodes had to download entire blobs to verify data availability — limiting scalable data throughput to ~3–6 blobs per block.
Sampling Instead of Downloading
PeerDAS (Peer Data Availability Sampling) introduces:
- Random sampling instead of full blob downloads
- Reed-Solomon erasure coding for recoverability
- Lower bandwidth requirement per node
- Massive DA scaling, targeting 64+ blobs per block in future updates
Because nodes only download tiny random pieces, the network can safely increase total blob capacity without overwhelming home stakers.
BPO Forks (EIP-7892): Ethereum’s New “Volume Knob”
BPO = Blob-Parameter-Only fork
Before Fusaka, increasing blob capacity required a full hard fork.
Now Ethereum can adjust blob limits without a major network upgrade.
Scheduled Capacity Increases
- Dec 3, 2025 — Fusaka mainnet launch
- Dec 9, 2025 — BPO1 (+67% blobs)
- Jan 7, 2026 — BPO2 (+133% total increase)
This introduces a flexible system that lets Ethereum match DA capacity to real-time demand.
Data Throughput Roadmap (Blobs per Block)
1 | Current (Dencun) : ▇▇▇ (3 Target / 6 Max) |
This roadmap illustrates Ethereum’s aggressive scaling strategy, moving from the current 3-6 blob capacity to a future target of 64+ blobs per block through PeerDAS implementation.
Impact on Alt-DAs (Celestia, EigenDA, Avail)
Fusaka doesn’t destroy Alt-DAs — it compresses their margins.
Side-by-Side Comparison
| Feature | Ethereum (Fusaka) | Alt-DAs (Celestia, EigenDA, Avail) |
|---|---|---|
| Throughput | High (PeerDAS scaling) | Very High (DA-first chains) |
| Cost | Low | Lowest |
| Security | Gold Standard (ETH L1) | Smaller validator sets / restaking |
| Use Case | General rollups + L2s | Ultra-high throughput apps |
The Squeeze
General-purpose rollups like Arbitrum, Optimism, Base, and zkSync will see fees fall significantly.
Their incentive to migrate to Alt-DAs decreases.
The Pivot for Alt-DAs
- Celestia will target bandwidth-heavy use cases (gaming, social, on-chain compute).
- EigenDA benefits indirectly because Fusaka increases the L1 gas limit (EIP-7935), lowering proof costs.
Other Goodies in Fusaka
These upgrades ship alongside the DA improvements:
1. EIP-7935 — Gas Limit Increase
Block gas limit doubles from 30M → ~60M, increasing L1 computation capacity.
2. EIP-7951 — Passkey Support
Adds secp256r1 cryptography, enabling FaceID/TouchID wallet authentication.
3. EIP-7934 — Max Block Size Cap
Caps blocks at 10 MB to prevent data-flood attacks.
4. EIP-7825 — Per-Transaction Gas Cap
Prevents one transaction from consuming an entire block.
Summary
Fusaka isn’t just an upgrade — it’s a defensive maneuver.
By introducing PeerDAS, BPO forks, and gas limit expansions, Ethereum positions itself as:
- Cheaper
- Higher throughput
- More flexible
- More competitive against modular DA chains
For 90% of rollups, Ethereum’s DA becomes “good enough,” reducing the economic pressure to migrate to external DA layers.
External DA still matters — but only for applications that require extreme bandwidth (e.g., gaming, AI, fully on-chain compute).
Ethereum has effectively said:
“We can be modular too — and we’re not giving up the DA market.”