Why genesis block is must for a peer to join the channel in Hyperledger fabric?

Question

For peers to join the channel, the information of genesis block is must.

Why peers required genesis block?

I knew that channel configuration stored in genesis block but
latest channel configuration also available in recent blocks then why only genesis only?

Does the genesis block provide any additional information?

Answer 1

When you update the channel configuration, the new block has the information of the new channel configuration. For example, if a new org enters to the channel, its anchor peer need the genesis block to download the chain from the beginnig, to store and update the state of the blockchain.

Hyperledger Fabric Docs Quote - Join Org3 to the Channel:

... we are passing a 0 to indicate that we want the first block on the channel’s ledger (i.e. the genesis block). If we simply passed the peer channel fetch config command, then we would have received block 5 – the updated config with Org3 defined. However, we can’t begin our ledger with a downstream block – we must start with block 0.