tidb pd中region分布 不均匀 对应的几个scheduler的状态是halt

【TiDB 使用环境】生产环境
【TiDB 版本】7.5.1
【操作系统】龙蜥7.9
【部署方式】机器部署（160G内存、磁盘1.1T）
【集群数据量】 173.5G
【集群节点数】1
【问题复现路径】
单节点tidb集群，当时部署了三个tikv节点，因跑任务有时会报错反馈资源紧张，备份也会报region is unavailable 后 强制下线掉两个tikv节点（这里是个雷）后 报错，又扩容回3个tikv，扩容结束后集群正常，但region分布不均匀，原始正常的1个tikv节点数据目录200G，扩容的2个节点数据目录10G+。跑任务报错比之前频繁了，报错region is unavailable 或please make sure tidb can connect to tikv。
【遇到的问题：问题现象及影响】
单节点tidb集群，当时部署了三个tikv节点，因跑任务有时会报错反馈资源紧张，备份也会报region is unavailable 后 强制下线掉两个tikv节点（这里是个雷）后 报错，又扩容回3个tikv，扩容结束后集群正常，但region分布不均匀，原始正常的1个tikv节点数据目录200G，扩容的2个节点数据目录10G+。跑任务报错比之前频繁了，报错region is unavailable 或please make sure tidb can connect to tikv。
影响就是偶发的region不可达

【资源配置】进入到 TiDB Dashboard -集群信息 (Cluster Info) -主机(Hosts) 截图此页面
【复制黏贴 ERROR 报错的日志】
pd的报错日志:
[2025/10/23 16:16:13.710 +08:00] [INFO] [prepare_checker.go:65] [“not loaded from storage region number is satisfied, finish prepare checker”] [not-from-storage-region=17584] [total-region=17584]
[2025/10/23 16:16:13.710 +08:00] [INFO] [coordinator.go:390] [“coordinator has finished cluster information preparation”]
[2025/10/23 16:16:13.710 +08:00] [INFO] [coordinator.go:400] [“coordinator starts to run schedulers”]
[2025/10/23 16:16:13.711 +08:00] [INFO] [coordinator.go:461] [“create scheduler with independent configuration”] [scheduler-name=balance-hot-region-scheduler]
[2025/10/23 16:16:13.713 +08:00] [INFO] [coordinator.go:461] [“create scheduler with independent configuration”] [scheduler-name=balance-leader-scheduler]
[2025/10/23 16:16:13.715 +08:00] [INFO] [coordinator.go:461] [“create scheduler with independent configuration”] [scheduler-name=balance-region-scheduler]
[2025/10/23 16:16:13.716 +08:00] [INFO] [coordinator.go:461] [“create scheduler with independent configuration”] [scheduler-name=balance-witness-scheduler]
[2025/10/23 16:16:13.720 +08:00] [INFO] [coordinator.go:461] [“create scheduler with independent configuration”] [scheduler-name=evict-leader-scheduler]
[2025/10/23 16:16:13.720 +08:00] [ERROR] [coordinator.go:464] [“can not add scheduler with independent configuration”] [scheduler-name=evict-leader-scheduler] [scheduler-args=“[4422294]”] [error=“[PD:scheduler:ErrSchedulerExisted]scheduler existed”]
[2025/10/23 16:16:13.720 +08:00] [INFO] [coordinator.go:461] [“create scheduler with independent configuration”] [scheduler-name=transfer-witness-leader-scheduler]
[2025/10/23 16:16:13.721 +08:00] [INFO] [coordinator.go:487] [“create scheduler”] [scheduler-name=balance-region-scheduler] [scheduler-args=“”]
[2025/10/23 16:16:13.721 +08:00] [INFO] [coordinator.go:487] [“create scheduler”] [scheduler-name=balance-leader-scheduler] [scheduler-args=“”]
[2025/10/23 16:16:13.722 +08:00] [INFO] [coordinator.go:487] [“create scheduler”] [scheduler-name=balance-witness-scheduler] [scheduler-args=“”]
[2025/10/23 16:16:13.722 +08:00] [INFO] [coordinator.go:487] [“create scheduler”] [scheduler-name=balance-hot-region-scheduler] [scheduler-args=“”]
[2025/10/23 16:16:13.722 +08:00] [INFO] [coordinator.go:487] [“create scheduler”] [scheduler-name=transfer-witness-leader-scheduler] [scheduler-args=“”]
[2025/10/23 16:16:13.722 +08:00] [INFO] [coordinator.go:487] [“create scheduler”] [scheduler-name=evict-leader-scheduler] [scheduler-args=“[4422294]”]
[2025/10/23 16:16:13.722 +08:00] [INFO] [coordinator.go:487] [“create scheduler”] [scheduler-name=evict-leader-scheduler] [scheduler-args=“[1]”]
[2025/10/23 16:16:13.726 +08:00] [INFO] [coordinator.go:256] [“coordinator begins to check suspect key ranges”]
[2025/10/23 16:16:13.726 +08:00] [INFO] [coordinator.go:320] [“coordinator begins to actively drive push operator”]
[2025/10/23 16:16:13.726 +08:00] [INFO] [coordinator.go:147] [“coordinator starts patrol regions”]
[2025/10/23 16:19:03.542 +08:00] [WARN] [grpclog.go:60] [“grpc: Server.processUnaryRPC failed to write status: connection error: desc = "transport is closing"”]
[2025/10/23 16:19:22.445 +08:00] [WARN] [heartbeat_streams.go:165] [“send keepalive message fail, store maybe disconnected”] [target-store-id=12250001] [error=EOF]

Start with the TiDB 7.5.1 deployment details, the TiDB Dashboard cluster information, and the PD logs showing halted schedulers and disconnected TiKV stores. No documentation page or code entry point is identified; determine whether this report belongs in the documentation and define the expected diagnostic or recovery guidance before making a change.