The objective is to make the secondary master's file system exactly the same as the primary so that in the event of a failover, the system will function as it did prior to the failure. tar is used in order to preserve meta information (owner, date, permissions, etc) of the files. Thus, first the tar archives are created on the master and copied over to the secondary master (node 0). Then, the backup master file system partitions are mounted on the slave with the / directory mapped to /mnt/root, and the /var and /usr directories becoming /mnt/root/var and /mnt/root/usr. That accomplished, the tar files are unpacked into their file systems. Finally, the file systems are unmounted again so that they will be clean should failover be needed.
In summary:
tar --one-file-system /scratch/root.tar /
tar --one-file-system /scratch/var.tar /var
tar --one-file-system /scratch/usr.tar /usr
cd /scratch
bpcp root.tar var.tar usr.tar 0: (this step may take a moment)
bpsh 0 mkdir /mnt/root
mkdir /mnt/root
bpsh 0 mount /dev/hda3 /mnt/root
cd /mnt/root
bpsh 0 tar xvf /scratch/root.tar
bpsh 0 mount /dev/hda5 var
bpsh 0 tar xvf /scratch/var.tar
bpsh 0 mount /dev/hda6 usr
bpsh 0 tar xvf /scratch/usr.tar
bpsh 0 sync
bpsh 0 umount usr
bpsh 0 umount var
cd ..
bpsh 0 umount root