Unison

This procedure configures a hot backup server with unison.

1. Use this document to build a second mail server, but use a different computer name.

   (We use vmpulpy as the secondary mail server in this document.)

2. Use the ssh command on the secondary computer at least once so that the /root/.ssh directory is properly created.

   # ssh localhost

3. Create an ssh keypair on the primary server as the root user.

   # ssh-keygen -t dsa
   [screenshot]

   Accept the defaults for all ssh-keygen questions:
   Enter a file in which to save the key (/root/.ssh/id_dsa): [empty]
   Enter passphrase (empty for no passphrase): [empty]
   Enter the same passphrase again: [empty]

4. Copy the /root.ssh/id_dsa.pub file to the secondary server as the /root/.ssh/authorized_keys file.

   # scp /root/.ssh/id_dsa.pub vmpulpy.local:/root/.ssh/authorized_keys

   Note: You will be prompted for a password.

5. SSH into the secondary server.

   # ssh vmpulpy.local

   You will not be prompted for a password if the keypair was properly installed.

6. Logout of the secondary server.

   # exit

7. Install unison.

   # apt-get install unison