When not using AtSync for LB, when does the LB start up? Where is the code that periodically checks if load balancing can be done?
If not using usesAtSync, the load balancer can start up at anytime. There is a dummy AtSync for each array element which by default tells the load balancer that it is always ready. The LDBD manager has a syncer (LBDB::batsyncer) which periodically calls AtSync roughly every 1ms to trigger the load balancing (this timeout can be changed with the +LBPeriod option). In this load balancing mode, users have to make sure all migratable objects are always ready to migrate (e.g. not depending on a global variable which cannot be migrated).
