Answer

1. Log on as root on ha1 and add a new Linux user:
   useradd databkp_usr
   echo "databkp_usr<CTRL j>databkp_usr"| passwd databkp_usr


2. Ensure the user was created successfuly. This command:
   grep databkp_usr /etc/passwd
should return something like:
   databkp_usr:x:503:503::/home/databkp_usr:/bin/bash

3. Log on as root on ha2 and add another user there with the same name and UID:
   ssh ha2
   useradd databkp_usr
   echo "databkp_usr<CTRL j>databkp_usr"| passwd databkp_usr
   grep databkp_usr /etc/passwd

4. Create database group with backup and restore privileges, and user:
   nzsql -c "Create Group BACKUP_USERS_GRP;"
   nzsql -c "Grant Backup, Restore To BACKUP_USERS_GRP ;"
   nzsql -c "Create User DATABKP_USR_DB With Password 'xxxxxxxx'
      In Group BACKUP_USERS_GRP;"

5. Set environment variables in databkp_usr's .bashrc file on both ha1 and ha2
   cd ~databkp_usr
   cp ~nz/.bashrc .
   vi ./.bashrc

Add or change these lines:
   # For NPS
   export NZ_USER=databkp_usr_db # Default NZ username#
   export NZ_PASSWORD=xxxxxxxx # Default NZ password
   export NZ_DATABASE=system   # Default NZ database
   export NZ_HOST=$(hostname)

6. Login as databkp_usr and take a backup on both ha1 and ha2 to confirm it all works:
   nzbackup -db sample_db -dir /tmp -v