gasLimit 5000 on private Ethereum geth node

Question

Problem: I've upgraded my geth node to the latest version (1.9.0-unstable). The block gasLimit of the node is fixed at 5000:

eth.getBlock("latest").gasLimit

5000

When I try to send a transaction, I get the following error:

Error: exceeds block gas limit

Attempted fixes: I have tried to alter the default gasLimit value in the genesis.json:

"gasLimit": "0xffffffff"

From geth node command line option:

--targetgaslimit '9000000000000'

---

Point to note: On previous versions, i.e, before upgrading, the block gasLimit returned by the node was much higher and it let me deploy contracts and perform transactions.

eth.getBlock("latest").gasLimit

4286582786

Answer 1

As @fixanoid stated in his answer you can change the gas limit in the genesis.json.

But this isn't an optimal solution in my opinion. You are better off using a specific flag for your miner.

Geth has the --targetgaslimit flag that will cause your miner(s) to move step by step towards a given gas limit. Only a certain increase is allowed per block. Typically prev limit/1024. So it might take some time to get it where you want it to be. Obviously a larger change results in the block not being accepted.

Besides specifying the --targetgaslimit flag you also have to make your node --mine in your private blockchain (Obviously).

EDIT: How are you sending the transactions? What gas limit are you currently specifying? The minimum for a transaction is 21000. If you are invoking a contract with a fallback function even more gas is needed. Make sure you have enough ETH to pay for the gas.

The problem might be that the error message is flawed.

Answer 2

3 things to try:

• Avoid using unstable versions, switch to the last stable Elasa (v1.9.6)
• You may have to increase the gas a bit when deploying contracts, because of new versions of solidity where gas calculation changes
• Using a gas price oracle is sometimes needed

Answer 3

One way to do this is to set very high limit for gas in the genesis config file like so: "gasLimit": "0xE0000000". Alternatively, run a client optimized for private nets: https://github.com/jpmorganchase/quorum. Default gas limit is in billions.