We have a private network running on Hyperledger Besu. We are using ethash, and it had a fixed difficulty of 3625. That was producing blocks fairly quickly, averaged about 8-10 seconds, with some as high as a minute and a good number in fractions of a second.

Recently, we changed our genesis to remove the fixed difficulty, and use the "built in" difficulty parameter that would adjust over time. We set this initial difficulty to 0x1. We also reduced the gas limit per block from the maximum allowed by Truffle to the 30million cap currently allowed by main net Ethereum.

The problem is since we made those changes, block production has become insanely slow. The new chain produced about 100 blocks in 3 hours. 100 blocks should be roughly 25 minutes at 15 seconds per block. This not acceptable and not intended. We were trying to use the built in algorithm to keep with the 15 second block time instead of using a fixed difficulty with widely varying results.

We've been trying to figure out why reducing the difficulty has dramatically increased block time. It should be the opposite. I've pasted our genesis file below. Does anyone know why all of a sudden block time has gone sky high?

{
  "config": {
    "homesteadBlock":0,
    "byzantiumBlock":0,
    "constantinopleBlock": 0,
    "constantinopleFixBlock":0,
    "muirGlacierBlock":0,
    "berlinBlock":0,
    "chainID": 17000,
    "ethash": {}
  },
  "difficulty": "0x1",
  "gasLimit": "0x1C9C380",
  "nonce": "0x0",
  "timestamp":"0x0"
}