How do I know if my private net is using Byzantium?

Question

Is there a flag that is showing that Byzantium is actually enabled in my private network?

This is the only thing I have found in my log at geth startup:

INFO [10-26|01:10:40] Initialised chain configuration          config="{ChainID: 1111 Homestead: <nil> DAO: <nil> DAOSupport: false EIP150: <nil> EIP155: <nil> EIP158: <nil> Byzantium: <nil> Engine: unknown}"

But I am not sure if this data is meaningful.

Is there somthing like

>eth.bizantiumActive()
1

???

Answer 1

In your genesis config file, you should see config field, then set ByzantiumBlock to 0, like this

and make sure you geth version is greater than 1.7.0, you can send a simple transaction to the private network, and getTransactionReceipt, if you see status field not root field in the receipt, then Byzantium fork is live.

Answer 2

The trick that worked for me was to create a new node with an updated genesis (use geth v1.7.2). And add the new node as a peer to the old node (old node runs geth v1.6.7). They should be able to sync without problems.

You have to make sure both clients have generated the same block 0 from the genesis file. If the blocks are different the synchronization will not start and you will not be able to proceed.

After the new node is synchonized, you can shutdown the old node and start working in the new blockchain exclusively. You should mine some blocks until the byzantinumBlock is reached, and from there byzantinum features should be active in your private testnet.