# mkdir /server01/pgarchives
# chmod 700 /server01/pgarchives 
# chown postgres:postgres /server01/pgarchives

Enable archiving by modifying postgresql.conf:
File is generally located at /var/lib/pgsql/9.4/data/postgresql.conf
# WRITE AHEAD LOG
# - Settings - 
wal_level = hot_standby
# - Archiving
archive_mode = on
archive_command = 'cp %p /server01/pgarchives/%f'
# REPLICATION
# - Sending Server(s) -
max_wal_senders = 3

Add the postgres user to the replication role and grant permissions in pg_hba.conf by adding the following line to the end of the file:
local	replication		postgres			trust
 
Restart the postgresql server
Verify that Write Ahead Logging is enabled by checking the contents of the pg_xlog folder for files with names similar to 000000010000000000000001

This folder is located at /var/lib/pgsql/9.4/data/pg_xlog

Performing a hot backup using pg_basebackup:
Create a new folder as the postgres user
pg_basebackup --xlog --format=t -D /server01/pgbackup/`date %Y%m%d`

Restoring from Backup:
Extract the contents of base.tar from the backed up folder on top of the PostgreSQL installation folder:
tar -xf base.tar -C /var/lib/pgsql/9.4/data     (RedHat/CentOS)
Assuming that there is a single database tar file (named with a number) in the backup, extract the contents of this folder to the /server01 folder:
tar -xf <number>.tar -C /server01
Copy any unarchived WAL log files saved from the first step back into the pg_xlog folder appropriate for the OS
Ensure that both the PostgreSQL installation folder and the /server01 folder are owned by the postgres user:
# chown -R postgres:postgres /var/lib/pgsql/9.4/data         (RedHat/CentOS)
# chown -R postgres:postgres /server01     (All)
Create a recovery.conf file in the installation folder (/var/lib/postgresql/9.4/main/recovery.conf) with the following content and make sure it is owned by the postgres user:
restore_command = 'cp /server01/pgarchive/%f %p'
The restore_command value should be the functionally opposite command used to archive the WAL files as configured in postgresql.conf
In the backup configuration above, WAL files are copied from "%p" to "/server01/pgarchive/%f"
The restore_command, therefore, needs to copy from "/server01/pgarchive/%f" to "%p"
In addition, it is possible to specify a specific date/time to restore to in this file for a point in time recovery by adding the following line to recovery.conf:
recovery_target_time = '2020-0-25 15:32:24 EST'
If the recovery_target_time parameter is omitted, the database will be recovered to the most recent transaction
Start the PostgreSQL database
If all goes well, the recovery.conf file will be renamed to recovery.done upon completion
Check the syslog (/var/log/syslog) for information on any errors that might have occurred during startup
Confirm that the backup was successfully restored