Log Message:
-----------
Document use of rsync for file system backups.
Tino Wildenhain
Modified Files:
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pgsql/doc/src/sgml:
backup.sgml (r2.56 -> r2.57)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/backup.sgml.diff?r1=2.56&r2=2.57)