CentOS 7 PostgreSQL – Failed to Read Permission Data Directory in Mounted Partition

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I've a problem with start PostgreSQL 9.4 on Centos 7 Server. Because the partition /var/lib/pgsql/9.4/data/ (which contains PostgreSQL data) is full so I want to change to another partition.

/dev/sdb1               154685904  322500 146482752   1% /run/media/root/Data

I've used this command to copy all the old data to new data folder:

cp -a /var/lib/pgsql/9.4/data/ /run/media/root/Data/pgsql_data

Then I changed the directory to new data directory in postgresql.conf (/var/lib/pgsql/9.4/data)

data_directory = '/run/media/root/Data/pgsql_data/'     # use data in another directory

And then I try to restart PostgreSQL, here are errors:

postgresql-9.4.service - PostgreSQL 9.4 database server    
Loaded: loaded (/usr/lib/systemd/system/postgresql-9.4.service; enabled)    
Active: failed (Result: exit-code) since Wed 2015-03-11 09:17:21 ICT; 4s ago   
Process: 54975 ExecStop=/usr/pgsql-9.4/bin/pg_ctl stop -D ${PGDATA} -s -m fast (code=exited, status=0/SUCCESS)   
Process: 56133 ExecStart=/usr/pgsql-9.4/bin/pg_ctl start -D ${PGDATA} -s -w -t 300 (code=exited, status=1/FAILURE)   
Process: 56127 ExecStartPre=/usr/pgsql-9.4/bin/postgresql94-check-db-dir ${PGDATA} (code=exited, status=0/SUCCESS)  
Main PID: 54580 (code=exited, status=0/SUCCESS)

Mar 11 09:17:16 localhost.localdomain pg_ctl[56133]: LOG:  skipping missing configuration file "/run/media/root/Data/pgsql_data/postgresql.auto.conf" 
Mar 11 09:17:16 localhost.localdomain pg_ctl[56133]: < 2015-03-10 22:17:16.187 EDT FATAL:  could not read permissions of directory "/run/media/root/Data/pgsql_data": Permission denied 
Mar 11 09:17:21 localhost.localdomain pg_ctl[56133]: pg_ctl: could not start server 
Mar 11 09:17:21 localhost.localdomain pg_ctl[56133]: Examine the log output. 
Mar 11 09:17:21 localhost.localdomain systemd[1]: postgresql-9.4.service: control process exited, code=exited status=1 
Mar 11 09:17:21 localhost.localdomain systemd[1]: Failed to start PostgreSQL 9.4 database server. 
Mar 11 09:17:21 localhost.localdomain systemd[1]: Unit postgresql-9.4.service entered failed state.

Please help!

Best Answer

You are obviously missing some permissions in the new location.

I have tried to reproduce your error on my local test cluster. I could get several different errors along the way but never the one you got. However, here are the permissions you need on your directories to run the cluster:

  • the data_directory (in your case, pgsql_data) must be owned by postgres (the group seems making no difference)
  • it must have 0700 as permissions (no group and world level permissions are allowed)
  • all directories under this need 07XX, where XX refers to the group and world permissions - I haven't found any restrictions to these (but obviously didn't try all possibilities)

Based on my experiments, these should be enough for starting PostgreSQL.

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