FAILOVERPlanned zero-loss handover: quiesce writes, wait for the target replica to drain, promote it, and follow it.
| 语法 | FAILOVER host port [TIMEOUT ms] | ABORT |
| 分组 | replication |
| 参数个数 | -3 |
| 起始版本 | 3.0.0 |
| 标志 | write, admin |
| 复杂度 | O(1) at the command — the handover runs in the background, polling the target until it is caught up |
| Redis 兼容性 | differs: Redis's syntax is FAILOVER [TO host port [FORCE]] [ABORT] [TIMEOUT ms] with an optional target; kevy's is FAILOVER host port [TIMEOUT ms] | ABORT — the target is mandatory and positional, and the port given is the target's client port |