diff --git a/infrastructure/shared-postgresql/README.md b/infrastructure/shared-postgresql/README.md
index 2c2ef29..55c233b 100644
--- a/infrastructure/shared-postgresql/README.md
+++ b/infrastructure/shared-postgresql/README.md
@@ -116,7 +116,7 @@ dev 为 laptop `:9188`，仅监听实例内网地址。exporter 以实例 OS 用
 
 规则 `platform/observability/metrics/rules/shared-postgresql-sql.yaml`（PrometheusRule）以上游
 `postgres_mixin` 为底改写：采集/SQL 不通、复制回放落后 > 1 MiB（与 failover 阈值一致）、主库复制槽
-保留 > 1 GiB、WAL 归档失败、XID/MXID 年龄、客户端连接 > 80%、空闲事务 > 10 分钟、事务 > 1 小时、
+保留 > 1 GiB、主库落在 pve1（HDD）超过 15 分钟、WAL 归档失败、XID/MXID 年龄、客户端连接 > 80%、空闲事务 > 10 分钟、事务 > 1 小时、
 死锁、频繁请求 checkpoint。目标带 `env` 标签，Alertmanager 把 `env="dev"` 送到独立 dev 频道。
 
 2026-10-01 验证：隔离集成测试覆盖 peer+ident 登录（主/备/dev）、读取 `pg_stat_statements`、
diff --git a/platform/observability/metrics/rules/shared-postgresql-sql.yaml b/platform/observability/metrics/rules/shared-postgresql-sql.yaml
index 85ef67d..c70219a 100644
--- a/platform/observability/metrics/rules/shared-postgresql-sql.yaml
+++ b/platform/observability/metrics/rules/shared-postgresql-sql.yaml
@@ -24,6 +24,15 @@ spec:
           labels: {severity: warning, service: shared-postgresql}
           annotations:
             summary: '共享 PG {{ $labels.env }} {{ $labels.member }} 无法以监控角色执行 SQL'
+        # 正常 primary 在 laptop ZFS SSD；pve1 的数据盘是 HDD。自动切换后主库安全落到 pve1
+        # 不会触发任何“无主/多主”规则（2026-09-30 的切换整整一天无人察觉），所以单独提示回切。
+        # 15m 留给计划内切换演练。
+        - alert: SharedPostgresPrimaryOnStandbyHost
+          expr: pg_replication_is_replica{job="shared-postgresql-sql", env="prod", member="pg-pve1"} == 0
+          for: 15m
+          labels: {severity: warning, service: shared-postgresql}
+          annotations:
+            summary: 共享 PG 生产主库运行在 pg-pve1（HDD），请确认切换原因并计划回切 laptop
         - alert: SharedPostgresSqlCollectorFailing
           expr: pg_scrape_collector_success{job="shared-postgresql-sql"} == 0 or pg_exporter_last_scrape_error{job="shared-postgresql-sql"} == 1
           for: 10m
diff --git a/platform/observability/metrics/tests/shared-postgresql-sql.test.yaml b/platform/observability/metrics/tests/shared-postgresql-sql.test.yaml
index 724256b..60cc030 100644
--- a/platform/observability/metrics/tests/shared-postgresql-sql.test.yaml
+++ b/platform/observability/metrics/tests/shared-postgresql-sql.test.yaml
@@ -137,3 +137,29 @@ tests:
     - exp_labels: {job: shared-postgresql-sql, instance: 'p:9187', member: pg-pve1, env: prod, severity: warning, service: shared-postgresql}
       exp_annotations:
         summary: 共享 PG prod pg-pve1 有事务空闲未提交超过 10 分钟
+- name: 主库落在 pve1 持续 15 分钟提示回切
+  interval: 1m
+  input_series:
+  - series: pg_replication_is_replica{job="shared-postgresql-sql",instance="10.60.0.20:9187",cluster="homelab-pg-prod",member="pg-pve1",env="prod"}
+    values: '0x20'
+  - series: pg_replication_is_replica{job="shared-postgresql-sql",instance="192.168.10.127:9187",cluster="homelab-pg-prod",member="pg-laptop",env="prod"}
+    values: '1x20'
+  alert_rule_test:
+  - eval_time: 10m
+    alertname: SharedPostgresPrimaryOnStandbyHost
+    exp_alerts: []
+  - eval_time: 16m
+    alertname: SharedPostgresPrimaryOnStandbyHost
+    exp_alerts:
+    - exp_labels: {job: shared-postgresql-sql, instance: '10.60.0.20:9187', cluster: homelab-pg-prod, member: pg-pve1, env: prod, severity: warning, service: shared-postgresql}
+      exp_annotations:
+        summary: 共享 PG 生产主库运行在 pg-pve1（HDD），请确认切换原因并计划回切 laptop
+- name: 主库在 laptop 不提示
+  interval: 1m
+  input_series:
+  - series: pg_replication_is_replica{job="shared-postgresql-sql",instance="10.60.0.20:9187",member="pg-pve1",env="prod"}
+    values: '1x20'
+  alert_rule_test:
+  - eval_time: 16m
+    alertname: SharedPostgresPrimaryOnStandbyHost
+    exp_alerts: []