You have to stop the servers to backup... if you make a copy during no-activity on the server it would be risky but it would work. I"m not sure I would place it as a standard procedure.
This is because a journal has inter dependencies between the files where it add/delete records. Making a copy during the operation may give you an inconsistent result.
Ok, thanks for the reply!
If you're running Linux, this article http://www.cyberciti.biz/tips/consistent-backup-linux-logical-volume-manager-snapshots.html might be of help.
The article decribes the solution for the problem:
In a production environment many users access the same file (file is open) or database. Suppose you start backup process when a file is open, you will not get correct or updated copy of file i.e. inconsistent backup (see accurate definition of inconsistent backup).
Benefit of this approach is zero-downtime of HornetQ during backup, but still be able to create a consistent backup.