I tried to perform a backup with --no-lock and still get binary log pos of xtrabackup_logfile to initiate mysql replication.
I tried to do exactly what is described in this post below but i didn’t manage to get binary log pos after the prepare step
As –no-lock describes use this option if you don’t care backup binary log position so backup doesn’t contains xtrabackup_binlog_info file if backup is created with –no-lock option because –no-lock prevents FTWRL which is required to get consistent positions for binary log. If you are taking backup from master to provision new slave i suggest to do during offpeak time. This should help you regarding provisioning new slave [url]Percona XtraBackup
If all your database tables are InnoDB then surely no downtime because as i said it will only take FTWRL for very short time to copy .frm files. On the other hand if you using MyISAM tables then FTWRL blocks the all tables to copy .MYD, .MYI, .FRM files