After three successful trials on the Holesky, Sepolia and Hoodi testnet, Ethereum’s Fusaka hardfork will go live on mainnet on December 3.
It’s the most eagerly anticipated upgrade to Ethereum since the last one, Pectra — although Fusaka will have a much more significant impact, enabling rollups to scale in the space of a month up to 1,000 transactions per second (TPS) and to 100,000 TPS over time.
It’s actually two separate hard forks: the Fulu upgrade to the consensus layer (the part of a blockchain where validators in the network agree on what happened) and the Osaka upgrade to the execution layer (the part that actually processes transactions).
In the future, the consensus layer will be rebuilt as Lean Consensus (formerly known as Beam Chain but renamed after a trademark dispute) and hardened for security and decentralization with finality in seconds.
As part of the Lean Ethereum roadmap, validators on the execution layer will switch from reexecuting transactions to simply verifying tiny zero-knowledge proofs, enabling the L1 to scale to 10,000 TPS.
But that’s the long-term vision, expected to be completed within five years. Let’s take a look in detail at what improvements will occur in a little over two weeks’ time with Fusaka.
Sure, but what is PeerDAS?
Peer data availability sampling (PeerDAS) is a clever method to enable Ethereum to handle a lot more data, which enables L2s and rollups to scale up throughput.
The reason blockchains are a source of truth is because every computer in the network repeats the work of all the other computers in the network and agrees on the result, which is then recorded immutably.
This is, of course, horribly inefficient and means the blockchain’s speed is limited by the slowest computers, with the worst download speeds, on the network.
Ethereum makes this issue worse as its commitment to decentralization means it keeps the tech specs for validators and nodes at a consumer-grade level. (Current recommendations are closer to a gaming laptop than the Raspberry Pi of legend but are still within reach of a large number of people around the world.)
PeerDAS can be thought of as similar to torrenting for blockchains — instead of making everyone on the network download and upload the whole file, PeerDAS enables them to process just a small part. The whole thing — the blob — can be reconstructed later by assembling the components. This increases throughput considerably.
OK, but what are blobs in Ethereum?
L2s process transactions away from Ethereum to free up capacity on the L1. They then post transaction data in various forms back on Ethereum so everyone can be confident it’s legit and can resurrect the state of the L2 if needed. More transactions mean the L2s need to post more data on Ethereum.
Blobs were introduced in the March 2024 Dencun upgrade to store 128 kilobytes of data each. The system started with a three-blob target (but could stretch to six, with higher fees to discourage use during periods of heavy demand), and that doubled to six (max. nine) in the Pectra upgrade.
That space is already full, and the network is also running up against the limits of what it can handle because every node and validator has to download every blob. That’s particularly tough for solo stakers — validators running on laptops and home desktops.
Lucas Saldanha, blockchain protocol engineer with the Teku client, explains that a core concept underpinning Ethereum’s decentralization is “that anyone can run it.”
“But if we keep increasing storage and network requirements, it gets to a point where the regular person won’t be able to keep up anymore.”
PeerDAS splits the blobs into 128 separate “columns” and allows validators and nodes to download just a few of them. This increases the amount of data Ethereum can handle by a factor of eight, which enables the L2s to process eight times more transactions than they currently do, as they now have somewhere to post that transaction data at an affordable cost.
“The simplest way of thinking about PeerDAS would be making it in a way where even though we have more blobs, each server or each node doesn’t have to download all of them,” says Saldanha. “But you still have the same properties of knowing that the data is available if you need and, second, knowing that the data is the correct data.”
Ethereum blobs are not forever
Back in the old days, everyone stored every bit of data forever, but to avoid endlessly massively increasing storage requirements as the L2s scale up, blob data now only needs to be kept for 18 days. With six blobs, validators need to store 90GB of data…
cointelegraph.com