由于重启服务器，需要重新启动 postgres
之前重新映射postgres的data目录为其他数据盘，重启的时候出现以下错误
5月 27 14:36:30 xydc-pre01 systemd[1]: Starting PostgreSQL 12 database server... -- Subject: Unit postgresql-12.service has begun start-up -- Defined-By: systemd -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel -- -- Unit postgresql-12.service has begun starting up. 5月 27 14:36:30 xydc-pre01 postgresql-12-check-db-dir[10368]: "/var/lib/pgsql/12/data/" is missing or empty. 5月 27 14:36:30 xydc-pre01 systemd[1]: postgresql-12.service: control process exited, code=exited status=1 5月 27 14:36:30 xydc-pre01 postgresql-12-check-db-dir[10368]: Use "/usr/pgsql-12/bin/postgresql-12-setup initdb" to initialize the database cluster. 5月 27 14:36:30 xydc-pre01 postgresql-12-check-db-dir[10368]: See /usr/share/doc/postgresql12-12.5/README.rpm-dist for more information. 5月 27 14:36:30 xydc-pre01 systemd[1]: Failed to start PostgreSQL 12 database server. -- Subject: Unit postgresql-12.service has failed -- Defined-By: systemd -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel -- -- Unit postgresql-12.service has failed. -- -- The result is failed. 5月 27 14:36:30 xydc-pre01 systemd[1]: Unit postgresql-12.service entered failed state. 5月 27 14:36:30 xydc-pre01 systemd[1]: postgresql-12.service failed. 5月 27 14:36:30 xydc-pre01 polkitd[596]: Unregistered Authentication Agent for unix-process:10361:1070035 (system bus name :1.1214, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale zh_CN.UTF-8) (disconnected from bus) 5月 27 14:36:32 xydc-pre01 polkitd[596]: Registered Authentication Agent for unix-process:10434:1070303 (system bus name :1.1215 [/usr/bin/pkttyagent --notify-fd 5 --fallback], object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale zh_CN.UTF-8) 5月 27 14:36:32 xydc-pre01 polkitd[596]: Unregistered Authentication Agent for unix-process:10434:1070303 (system bus name :1.1215, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale zh_CN.UTF-8) (disconnected from bus)
由于数据库需要快速恢复，查验了/var/lib/pgsql/12/data/，就是把原来的数据拷贝回原来的目录，还是失败。
由于使用的是 root 用户进行操作的，拷贝完之后，还是不能重启
明明已经存在，但是还是有问题。
"/var/lib/pgsql/12/data/" is missing or empty.
最后发现是当前目录没有权限
chown -R postgres:postgres /var/lib/pgsql/12/data
然后数据库重启成功
