Iris — Complete Sharding on Partisia Blockchain

There are 7 proprietary innovations that deliver Partisia Blockchain’s complete Layer 1+2 Blockchain. In this blog we present the second innovative feature — the sharding model — we call it Iris.

For an overview of all of the 7 features see the Zeus blog. We present each of the 7 innovations with a unique post leading up to TGE on May 31, 2022.

Iris — Complete Sharding

The so-called blockchain trilemma is all about the difficulties in designing a blockchain that can scale to handle any number of transactions without hampering secure decentralization. The key to unlocking this challenge is sharding, which is the art of parallelizing consensus without compromising security:

  1. Decentralization, meaning that all eligible nodes can become part of the blockchain consensus
  2. Security, in the sense that the blockchain does not become vulnerable to a dominating fraction of malicious nodes.

Partisia Blockchain solves the blockchain trilemma through sharding involving all baker nodes across all shards as a genuine layer 1. This way, sharding does not impact the Poseidon provable consensus model and hence neither diminish decentralization nor the overall threshold security model.

An illustration of the scalable block creation where each shard creates verifiable blocks according to the consensus model presented in the Poseidon blog is provided below. The consolidated blockchain shows how the sharding scales linearly in the number of shards i.e. a blockchain running with three shards can handle three times as many concurrent transactions as a blockchain running without sharding. To see this, note that the consensus process, including the time consuming propagation of messages, is done in parallel and independently across shards. A governance shard keeps track of the shards and distributes the block creation work across the independent shards. Also, the security model ensures that all new nodes are properly represented across all shards and thereby validate every transaction.

This way, the capacity of the Partisia Blockchain can be scaled up to meet any number of transactions per second (TPS). The capacity of a shard is roughly 1,000 TPS and a new shard is just one transaction away. Even in the rare case of a time consuming full BFT reset on one shard, the workload allocated to other shards and the impact on the capacity of the entire blockchain will be marginal only.

Sharding is an integrated part of the initial version of the Partisia Blockchain and will gradually be developed to dynamically adjust for throughput by spinning up new shards on demand exactly as cloud computing allows dynamic load balancing.

For more details, please checkout the yellow paper and software documentation.

Please let us know what you think and stay tuned for the next blog post about our collateralized token bridging, called Hermes.

Thank you to everyone in our community for your support!

Partisia Blockchain Team