title: Can't start postgres on linux
body: <p>When I run <strong>sudo -u postgres psql</strong> it gives error as</p>
  
  <pre><code>psql: could not connect to server: No such file or directory
      Is the server running locally and accepting
      connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
  </code></pre>
  
  <p>So I check status by <strong>pg_lsclusters</strong> ,it gives status as down</p>
  
  <p>So I tried to start the cluster by <strong>sudo pg_ctlcluster 11 main start</strong>,it gives error as </p>
  
  <pre><code>Job for postgresql@11-main.service failed because the service did not take 
  the steps required by its unit configuration.
  See "systemctl status postgresql@11-main.service" and "journalctl -xe" for 
  details.
  </code></pre>
  
  <p>Then I check log by <strong>journalctl -xe</strong> ,it gives </p>
  
  <pre><code>-- Subject: Unit postgresql@11-main.service has begun start-up
  -- Defined-By: systemd
  -- Support: http://www.ubuntu.com/support
  --
  -- Unit postgresql@11-main.service has begun starting up.
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: Error: 
  /usr/lib/postgresql/11/bin/pg_ctl /usr/lib/postgresql/11/bin/pg_ctl start -D 
  /data/aqu
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 
  18:35:50.032 UTC [3622] LOG:  listening on IPv4 address "0.0.0.0", port 5432
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 
  18:35:50.032 UTC [3622] LOG:  listening on IPv6 address "::", port 5432
   May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 
   18:35:50.033 UTC [3622] LOG:  listening on Unix socket 
   "/var/run/postgresql/.s.PGS
   May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 
   18:35:50.090 UTC [3623] LOG:  database system shutdown was interrupted; 
   last known
   May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 
  18:35:50.140 UTC [3623] LOG:  database system was not properly shut down; 
  automati
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 
  18:35:50.147 UTC [3623] LOG:  redo starts at 9D/44F48998
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 
   18:35:53.483 UTC [3624] a2i@postgres FATAL:  the database system is 
   starting up
   May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 
   18:35:54.422 UTC [3625] a2i@postgres FATAL:  the database system is 
  
  starting up
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 18:35:55.461 UTC [3626] a2i@postgres FATAL:  the database system is starting up
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 18:35:55.465 UTC [3627] a2i@postgres FATAL:  the database system is starting up
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 18:35:57.713 UTC [3628] a2i@postgres FATAL:  the database system is starting up
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 18:35:57.861 UTC [3623] LOG:  redo done at 9D/AFFFFF98
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 18:35:59.416 UTC [3629] a2i@postgres FATAL:  the database system is starting up
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 18:36:03.493 UTC [3630] a2i@postgres FATAL:  the database system is starting up
  May 08 18:36:07 ip-10-0-1-87 postgresql
  
  @11-main[3617]: 2019-05-08 18:36:04.431 UTC [3631] a2i@postgres FATAL:  the database system is starting up
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 18:36:05.471 UTC [3632] a2i@postgres FATAL:  the database system is starting up
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 18:36:05.477 UTC [3633] a2i@postgres FATAL:  the database system is starting up
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 18:36:06.776 UTC [3623] PANIC:  could not write to file "pg_wal/xlogtemp.3623": No
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 18:36:06.959 UTC [3622] LOG:  startup process (PID 3623) was terminated by signal
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 18:36:06.959 UTC [3622] LOG:  aborting startup due to startup process failure
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: 2019-05-08 18:36:07.108 UTC [3622] LOG:  database system is shut down
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: pg_ctl: could not start server
  May 08 18:36:07 ip-10-0-1-87 postgresql@11-main[3617]: Examine the log output.
  May 08 18:36:07 ip-10-0-1-87 systemd[1]: postgresql@11-main.service: Can't open PID file /var/run/postgresql/11-main.pid (yet?) after start: No such
  May 08 18:36:07 ip-10-0-1-87 systemd[1]: postgresql@11-main.service: Failed with result 'protocol'.
  May 08 18:36:07 ip-10-0-1-87 systemd[1]: Failed to start PostgreSQL Cluster 11-main.
  -- Subject: Unit postgresql@11-main.service has failed
  -- Defined-By: systemd
  -- Support: http://www.ubuntu.com/support
  --
  -- Unit postgresql@11-main.service has failed.
  --
  -- The result is RESULT.
  May 08 18:36:07 ip-10-0-1-87 sudo[3612]: pam_unix(sudo:session): session closed for user root
  </code></pre>
  
  <p>It may cause because of shutting down database improperly 
  I don't need solution like taking dump of existing database and reinstall postgres and restore it..I have big data , it will take much.
  What will be the soultion to sort this?</p>