What Is Sharding?

Sharding is a technique to partition databases that can be used to scale blockchains. It allows blockchains to process more transactions per second, also known as higher throughput. Sharding splits the blockchain network into smaller partitions. These so-called shards only process a part of the data of the entire blockchain, which makes them independent from other shards and relieves them of unnecessary computing.

Thanks to sharding, a network can compute more transactions and thus scale faster to transaction speeds known from centralized ledgers. On the other hand, critics point out that shards are liable to attacks and reduce network security.

How Does Sharding Work?

Blockchain networks are made up of nodes that validate the transactions in a network. Nodes are independent of one another and store the historical data of a blockchain. All full nodes store the entire history of a blockchain, which increases a blockchain's security and decentralization but slows down its transaction speed.

Sharding partitions the workload of nodes across different shards. In essence, not every node has to validate each transaction, which unnecessarily strains nodes and slows down the network. Instead, the work is compartmentalized across different shards. The blockchain databases are partitioned horizontally, meaning the different shards are split according to their characteristics. For instance, shards can be responsible for storing transactions of a specific type, while other shards can be divided based on the type of crypto asset they store.

The result is that not each node confirms each transaction. This drastically reduces a blockchain's workload and increases its speed.

How Secure Is Sharding?

Sharding has been criticized for potentially decreasing a blockchain's decentralization and security. Shards could be corrupted, with one shard taking over another shard, which could lead to a loss of information or data.