What is sharding?
Sharding is a scaling technique used in distributed computing and database systems, where data is partitioned into smaller subsets called “shards” and each shard is stored and processed separately across different servers or nodes.
In blockchain technology, sharding is used to increase the transaction processing capacity of a blockchain network, by dividing the blockchain database into smaller shards that can be processed by different nodes simultaneously.
Sharding in layman’s terms
Derived from the word shard meaning “a small piece of something big”, sharding in blockchain technology is the name of a process that divides a blockchain network into smaller partitions (known as shards) and increases its efficiency and scalability.
In simpler terms, its main motive is to remove the extra pressure from the main blockchain network and speed up the transaction verification process by splitting the main blockchain into different partitions.
Think of the main blockchain as a big 10,000-piece puzzle being solved by 10 people. In this case, sharding would be making 5 teams of 2 people each. Each team will get 2000 puzzle pieces to solve. You can refer to the 5 teams as shards.
Now, earlier each person was responsible for solving 10,000 puzzle pieces because there was no systematic distribution. With sharding, each person is responsible for solving only 1000 pieces of the puzzle. This will increase efficiency and the speed of solving the puzzle.
How does sharding work?
There are some blockchains in the crypto world today that have an increased user base. As a result, they face scalability problems. Sharding, thus, is one of the approaches used to resolve the issue at hand.
The first step is to divide the main blockchain network into different partitions known as shards. Each shard will be responsible for a portion of the network’s transactions.
After the division and allocation of transactions to each shard, nodes are assigned to each one of them. These nodes help with the verification process of the transactions.
The nodes use a consensus mechanism – be it Proof-of-Work (PoW) or Proof-of-Stake (PoS) – which helps them stay in coordination with each other and maintain the integrity of the network and the authenticity of the transactions.
There can be transactions that would require multiple shards to communicate with each other through nodes. To assist the nodes in such a case, techniques like state channels and side chains – scalability techniques that work in parallel to the main blockchain – are used.
However, unlike some scalability techniques that are better suited for a specific consensus mechanism, sharding is applicable to both PoS and PoW consensus system along with Byzantine Fault Tolerance and other consensus systems.
Features of sharding
Sharding helps get the weight off of large databases and can help scale them horizontally. Here’s what the method can do:
- It makes any database smaller
- It makes any database faster
- It makes any database easier to manage
- It reduces the cost of transactions of any database
Sharding vs. partitioning: the difference
There is another term like sharding i.e. partitioning. Even though on surface level they may seem similar, both are not to be confused.
While they do break up large data into subsets, the main difference between them is that in former the data can be distributed among different computers and multiple servers. Partitioning, on the other hand, is used for grouping subsets of data within a single database substance.
Different sharding techniques
As mentioned earlier, sharding is quite interoperable in its nature. Its workings majorly depend on and are in compliance with a network’s demands, instructions, and consensus mechanism. Here are some techniques:
1. Network Sharding
This is the most common and also the most used technique. In network sharding, a blockchain network is divided into multiple shards and assigned nodes that verify a portion of the transactions. The shards operate in parallel to the main network and to each other as well. An example of a blockchain using this technique is known as Zilliqa.
2. State Sharding
State sharding is not much different from network sharding. In state sharding, the focus is on the state of the network. Contrary to the partition of the network into multiple shards, in state sharding, the blockchain state is divided into further multiple states.
This can improve the efficiency of the blockchain by reducing the storage and computational requirements of each node in the network. Ethereum 2.0 is a good example of a blockchain using state sharding.
3. Transaction Sharding
Transaction sharding is also not much different from network sharding. The only difference is that in transaction sharding, the partitioning and creation of shards are done based on the transactions.
Whereas, in network sharding, the entire blockchain network is partitioned into sub-networks called shards.
4. Hybrid Sharding
Hybrid sharding, as the name goes, is the hybrid of two or more of the aforementioned techniques. An example of hybrid sharding is the sharding solution used by Ethereum which uses a combination of state and network sharding.
Benefits of sharding
Here are some of the very many benefits of sharding.
The number one benefit of sharding is that it increases the scalability of a blockchain to a great extent. The parallel processing feature of sharding is a game-changer when it comes to the problem of scalability.
2. Increased storage
With sharding, the pressure from the main blockchain is taken off. For blockchains with a bigger user base, storage is a big problem. Sharding resolves this problem without slowing down the process. If there is anything that sharding reduces, it is the time taken by the main network to verify the transactions.
3. Increased efficiency
Sharding can also improve the efficiency of blockchain systems by reducing the processing requirements of each node. Since each node only needs to process a subset of the transactions, the processing power required for each node can be reduced, leading to a faster turnaround time.
4. Interoperability and flexibility
Sharding is interoperable in its workings. Its processes and techniques can be molded depending on the requirements of a blockchain. Thus, it is flexible in its workings.
Challenges of sharding
Here are a few challenges that you may face with sharding.
1. Security is a challenge
Shards can pose security challenges because even if one shard, or all the other shards, is compromised, it can lead to a disruption in the whole network. Thus, with multiple shards working in parallel with the network, the responsibility of ensuring the safety of the network also increases.
2. Data and information
Shards can’t work if they don’t have access to the required sources and necessary information and data. Ensuring that each shard has what it requires is quite some work that requires attention and monitoring.
3. External help
Communication is the key to shards because they work in parallel. But sometimes, like in the case of multiple shards getting into contact with each other to verify a transaction, the shards need external help from say, sidechains and state chains.
All in all, most important reason for using sharding is that it solves the scalability problem. Because shards are smaller, thus easier to manage, it boosts performance of the database as well as reduces the cost.
Moreover, sharded databases remain more strong in the face of any outages and offer high availability when data in the event of missing data chunks. If a database is not sharded, it risks going completely offline until the problem is fixed.
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