why can not stop mining in geth console?

Question

System information

Geth version: geth version Version: 1.6.6-unstable Architecture: amd64 OS & Version: Windows/Linux/OSX win10

Expected behaviour

I create a private chain in my pc. After mining for a while, I just want to stop mining

Actual behaviour

,so I type "miner.stop()", but it can't stop. the console still show information incessantly.

> INFO [07-07|09:42:20] Successfully sealed new block            number=203 hash=c11ed3…0bec95
INFO [07-07|09:42:21] 🔗 block reached canonical chain          number=198 hash=769f09…0fdd3f
INFO [07-07|09:42:21] 🔨 mined potential block                  number=203 hash=c11ed3…0bec95
INFO [07-07|09:42:21] Generating DAG in progress               epoch=1 percentage=72 elapsed=24m35.334s
INFO [07-07|09:42:21] Commit new mining work                   number=204 txs=0 uncles=0 elapsed=0s
> miner.stop()
true
> INFO [07-07|09:42:27] Generating DAG in progress               epoch=1 percentage=73 elapsed=24m40.957s
INFO [07-07|09:42:30] Generating DAG in progress               epoch=1 percentage=74 elapsed=24m43.627s
> miner.stINFO [07-07|09:42:32] Generating DAG in progress               epoch=1 percentage=75 elapsed=24m46.275s
> miner.stop()
true
> INFO [07-07|09:42:36] Generating DAG in progress               epoch=1 percentage=76 elapsed=24m49.595s
INFO [07-07|09:42:39] Generating DAG in progress               epoch=1 percentage=77 elapsed=24m52.717s

> miner.INFO [07-07|09:42:42] Generating DAG in progress               epoch=1 percentage=78 elapsed=24m55.622s
> miner.stop()
true
> INFO [07-07|09:42:45] Generating DAG in progress               epoch=1 percentage=79 elapsed=24m58.961s
INFO [07-07|09:42:48] Generating DAG in progress               epoch=1 percentage=80 elapsed=25m2.255s
INFO [07-07|09:42:52] Generating DAG in progress               epoch=1 percentage=81 elapsed=2

Answer 1

The first time you start mining will take some time as your node will need to generate a 1GB dataset for the Proof of Work algorithm. You will see “generating DAG” messages in the other console log, which took about 8 minutes on my laptop. You can read more about this here:

https://github.com/ethereum/wiki/wiki/Ethash-DAG

Source:

https://medium.com/@mikesmolenski/getting-started-with-ethereum-4a3841276b6e

Answer 2

miner.stop() will stop the mining likely after the running process is finished. You probably still have a handful of process that need to be finished. I was using ethereum private chain with PoA consensus and miner.stop() does stop the mining.