[CentOS] Copying a live system

Timothy Murphy
2016-05-03T13:55:11Z

I want to backup my current CentOS-7.2 system to another drive.
Is it safe to copy the system while it is running?
Eg by
mount /dev/sdb5 /mnt
rsync -HPaxvz /. /mnt/
I've found contradictory advice on the web.

--
Timothy Murphy
gayleard /at/ eircom.net
School of Mathematics, Trinity College, Dublin