is it ok to use the same WIF key for few mining accounts?
and to use the same accountname in --witness and --miner ?
1. only use --witness on one machine or you will double produce blocks and lose your account
2. you can use the same key so long as you mine on the same computer in the same process
I don't understand what the above is supposed to mean.
You have to set --witness only on one machine, but you can only mine with the same key on the same computer in the same process? Then what's the point? Doesn't this mean that you have to use a different key + witness for every "miner" that is setup? So wouldn't that make setting up a miner without the --witness option completely useless?
If not, how is one supposed to configure multiple miners on a single witness-account?
In STEEM chain, blocks are produced by witnesses.
Which block should be produced by which witness, is calculated at the start of each 'round' (every 21 blocks), as a consensus by every node.
By specifying --witness plus a key (which is in --miner), the node will produce blocks with that witness.
So if two machines have same witness and key, both of them will produce a block when it's the witness's turn. This is the so-called "double produce".
By specifying --miner but no --witness, the node will only mine with that miner but won't produce blocks. So it's possible to have multiple processes/hardware work for one witness.
So what's the use case? Assume there are 100 machines, each machine has the hashing power to keep 1 'ticket' in the queue, what's the easiest way to setup them? Probably run one server with --witness and --miner (specify 100 times with 100 different accounts), and other 99 servers with --miner and no --witness (with all 100 accounts as well). Or maybe even better if use more accounts.
//Update:
It's possible to specify --witness & --private-key but no --miner, so the node will produce blocks only, but won't mine. In this way an elected witness won't get voted out by itself when accidentally mined out a ticket.
//Update2:
Theoretically it would be somehow inefficient if use same key on different machines.