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Avoiding Equivocation

There's a very small set of behaviors that a miner in Spacemesh is punished for. If a miner simply goes offline or fails to publish a proposal when they're eligible to do so they'll miss some rewards but they're not punished per se. However, if a miner double votes, otherwise known as equivocation, their miner identity is permanently disqualified from participation in consensus and from earning rewards in the future. In a permissionless blockchain like Spacemesh, equivocation is a serious offense that can have severe negative ramifications for the entire network, so this behavior cannot go unsanctioned. Once a miner's identity has been cancelled their PoST data is effectively useless. They must generate a new identity and reinitialize their PoST data. For more information, see Community Clarification: Equivocation.

It's not difficult to avoid equivocation: simply make sure that the same identity is never attached to two running nodes at the same time. Extra care must be taken any time a miner identity or its PoST data are copied or moved (since the miner identity lives in the PoST data directory).

Moving an Identity​

When moving a miner identity from one place to another, perform the following steps in the following order:

  1. Shut down the miner in the source location
  2. Copy the files to the new location (see previous section)
  3. Double-check that the old miner was shut down. Check again one more time to make sure. If you get this part wrong, you risk permanently disqualifying the miner identity for equivalence and invalidation of the PoST data.
  4. Make sure the key.bin file is intact in the new location. Compare it to the key.bin file in the old location and make sure the contents are the same. Delete the old key.bin file, or at the very least, rename it or move it to ensure that you don't accidentally run the same identity again on the old system.
  5. Start the miner in the new location. Make sure that you specify the correct smeshing-opts-datadir in the config, and make sure that the other smeshing-opts are the same as they were in the old system, and that they match the contents of the postdata_metadata.json file in the PoST datadir. Make sure that the miner found the data and was able to read it. (You should see the messages post setup completed, loaded the initial post from disk, and verifying the initial post in the log.)

Generating Multiple Identities​

You can use one system to generate multiple PoST identities - this is a common usage pattern for a user who wants to, e.g., generate multiple identities on a system with a GPU, then transfer them to other systems. However, once you've moved the PoST data files (postdata_*.bin) to their new location, and copied key.bin as well, make absolutely certain that key.bin has been removed in the source location. If the file still exists, the next PoST identity you generate will be identical to the prior one and equivocation may occur as a result.