This assume that you have configured and installed perl (/opt/csw/bin/perl) via pkg-get.

Install rsync:

	# pkg-get install rsync

Download rsnapshot:

	# wget http://rsnapshot.org/downloads/rsnapshot-1.3.1.tar.gz

Uncompress:

	# gunzip rsnapshot-1.3.1.tar.gz
	# tar xzvf rsnapshot-1.3.1.tar.gz

Configure:

	# cd rsnapshot-1.3.1
	# ./configure

Run make:

	# /usr/ccs/bin/make test
	# /usr/ccs/bin/make install

Create rsnapshot configuration file:

	# cp /usr/local/etc/rsnapshot.conf.default /usr/local/etc/rsnapshot.conf
	# ln -s /usr/local/etc/rsnapshot.conf /etc/

Reference:
http://rsnapshot.org/