Nodes play a crucial role in maintaining the integrity and security of the blockchain network. They work together to ensure that transactions are processed accurately and that the blockchain remains tamper-resistant.
There are 3 types of Nodes in a Hyperledger Fabric network: Orderer, Peer and Certificate Authority Nodes
The orderer nodes are responsible for maintaining the order and consistency of transactions on the blockchain. They ensure that all transactions are recorded in the correct order and that there are no conflicts between them. Spydra supports the Raft protocol which is the de-facto implementation of ordering service for Fabric v2.x networks.
Guidance on choosing orderer node size and number:
Every pre-configured network size provided by Spdra has a default size and number for the orderer nodes. You can change the number of orderer nodes while creating or joining a network.
All organizations need not deploy orderer nodes. Organizations that want to be part of the blockchain network consensus process should deploy orderer nodes.
The total number of orderers in the network should be an odd number as this is recommended for the Raft protocol.
Raft provides Crash Fault Tolerance (CFT). Having more number of nodes improve resiliency as more nodes can be lost and the ordering service can still be functional. A five node cluster, for example, can tolerate two down nodes, while a seven node cluster can tolerate three down nodes.
However, more nodes mean a larger communication overhead, which could eventually slow the network. Raft clusters of more than a few dozen nodes begin to see noticeable performance degradation.
Adding more number of nodes does not help with improving performance as orderer nodes are not load balanced. Choosing a higher size for the node does improve performance.
Clusters of three, five, seven, or nine orderer nodes in a network are the most popular.
For additional information on choosing orderer nodes, refer here.
The peer nodes are responsible for executing transactions, maintaining the ledger, and participating in the consensus process. They communicate with other peer nodes to validate transactions and reach a consensus on the state of the ledger.
Guidance on choosing peer node size and number:
Every pre-configured network size provided by Spdra has a default size and number for the peer nodes. You can change the number of peer nodes while creating or joining a network.
The size and number of the peer nodes have a direct bearing on the performance of the network.
Peer nodes are load balanced. So, increasing the size and number of nodes generally improves performance.
For additional guidance on choosing peer nodes, refer here.
The Hyperledger Fabric Certificate Authority (CA) node is responsible for managing the digital certificates and identities of network participants. It uses a Public Key Infrastructure (PKI) system to issue and manage digital certificates that are used to authenticate and authorize network participants.
Spydra provides a CA node for each organization by default and nothing additional needs to be done to enable this. The certificates and related keys are securely stored in a dedicated Hashicorp vault that is provisioned for each organization.