When's it shipping?
Shard chains should ship sometime in 2021, depending on how quickly work progresses after the Beacon Chain is launched. These shards will give Ethereum more capacity to store and access data, but they won’t be used for executing code. The details of that are still being figured out.
Sharding is the process of splitting a database horizontally to spread the load – it’s a common concept in computer science. In an Ethereum context, sharding will reduce network congestion and increase transactions per second by creating new chains, known as “shards”.
This is important for reasons other than scalability.
Sharding is a good way to scale if you want to keep things decentralized as the alternative is to scale by increasing the size of the existing database. This would make Ethereum less accessible for network validators because they'd need powerful and expensive computers. With shard chains, validators only need to store/run data for the shard they're validating, not the entire network (like what happens today). This speeds things up and drastically reduces hardware requirements.
Sharding will eventually let you run Ethereum on a personal laptop or phone. So more people should be able to participate, or run clients, in a sharded Ethereum. This will increase security because the more decentralized the network, the smaller the attack surface area.
With lower hardware requirements, sharding will make it easier to run clients on your own, without relying on any intermediary services at all. And if you can, consider running multiple clients. This can help network health by further reducing points of failure. Run an Eth2 client
When the first shard chains are shipped they will just provide extra data to the network. They won’t handle transactions or smart contracts. But they’ll still offer incredible improvements to transactions per second when combined with rollups.
Rollups are a "layer 2" technology that exists today. They allow dapps to bundle or “roll up” transactions into a single transaction off-chain, generate a cryptographic proof and then submit it to the chain. This reduces the data needed for a transaction. Combine this with all the extra data availability provided by shards and you get 100,000 transactions per second.
The plan was always to add extra functionality to shards, to make them more like the Ethereum mainnet today. This would allow them to store and execute smart contracts and handle accounts. But considering the transactions per second boost that version 1 shards provide, does this still need to happen? This is still being debated in the community and it seems like there are a few options.
Vitalik Buterin, when talking to Bankless podcast, presented 3 potential options that are worth discussing.
This would mean we don’t give shards the capability to handle smart contracts and leave them as data depots.
Perhaps there’s a compromise where we don’t need all shards (64 are planned right now) to be smarter. We could just add this functionality to a few and leave the rest. This could speed the delivery up.
Finally, perhaps we should revisit this debate when ZK snarks are firmed up. This is a technology that could help bring truly private transactions to the network. It’s likely that they’ll require smarter shards, but they’re still in research and development.
Here's some more thinking along the same lines:
- Phase One and Done: Eth2 as a data availability engine – cdetrio, ethresear.ch
This is still an active discussion point. We’ll update these pages once we know more.
The Eth2 upgrades are all somewhat interrelated. So let’s recap how the shard chains relate the other upgrades.
The beacon chain contains all the logic for keeping shards secure and synced up. The beacon chain will coordinate the stakers in the network, assigning them to shards they need to work on. And it will also facilitate communication between shards by receiving and storing shard transaction data that is accessible by other shards. This will give shards a snapshot of Ethereum’s state to keep everything up-to-date.The Beacon Chain
The Ethereum mainnet will exist as it does today even after the introduction of shards. However at some point, mainnet will need to become a shard so that it can transition to staking. It remains to be seen whether mainnet will exist as the only “smart” shard that can handle code execution – but either way, a decision will have to be made on phase 2 of sharding.The docking