Moving to RAID1

[Jerrin]

Hello,

i have a freebsd(7.3) dedicated server with one hard disk.It have partitions
for root and swap only.I want to setup RAID1 by adding one more hard disk.i
found in freebsd handbook about setting up RAID1
http://www.freebsd.org/doc/handbook/geom-mirror.html .I only have remote
access to the server.Will i lose data by doing it?Anyways to make  sure in
the procedure of setting up raid1 that i shouldn't have to go single user
mode or change something at the boot prompt when rebooting after this is
setup.

Thank you
Rihaz