Common RPC to check your node validator

@huglester, talking more about this, your observation is true but i want to explain why:
Phase 1: when staking new node, your node started to sync beacon block from zero to latest
Phase 2: a random number that gets from Bitcoin blockchain was used to determine which node to which shard. Your node is randomly assigned to a shard. Eg. shard_2, then it started to sync shard blocks, from zero to latest, let say latest block number is 1000
Phase 3: when your node become shard_2 committee validator, it started to validate block, eg.: validate block 1001 to 1200 of shard_2, your node earning reward for every block produced in shard_2, but full reward is only paid once at the end of epoch.
Phase 4: at the end of epoch, your node is swap out of committee, it stop sync shard_2 block but continue sync beacon

The process start over at phase_2, then there are 2 cases:

  1. your node assigned to shard_2 again => continue sync shard_2 block from 1200 to latest
  2. your node assigned to other shards => sync this shard block from zero to latest

That being said, you can copy chain data to another location/machine, just make sure file path is correct.

PS. Notice at Phase_3, due to internet speed, hardware specs of committee node, that made a shard produce more or less blocks than others, that why reward in each shard is different when epoch ended.