checkpoint机制是不是与多个group不好同时采用？因为多个group的话，每个group都有自己的镜像数据，新机器加入的话，难道每个group都要从旧机器接收镜像追赶进度，而每个group学完都会退出进程

[jettchen]

[lynn]

For better generality to phxpaxos，we need to consider a situation that different group with different state machine, so every group's logic must be independent. (include checkpoint logic)

For your case, there's a way to fix it, not very difficult.

1. Because each group is in the same process, each group can communicate easily.
2. Write some logic in StateMachine::LoadCheckpointState, to let the group that finishes first wait for other groups. For example, sleep.

[jettchen]

thanks