[SunHELP] query about ufsdump

[TAG DBA]

Hello,
A number of books give the following kind of examples for using ufsdump
$ ufsdump 0ucf /dev/rmt/0  /s3104/home1

Note that they are referring to the mount point - meaning that the file system
is mounted. However Sun manuals say that one should preferably unmount the
filesyste, before taking a ufsdump. Which means my example would look like:
$ ufsdump 0ucf /dev/rmt/0 /dev/rdsk/c0t1d30s4

This confuses me - is it allright to take a ufsdump while the file system
being backed up is mounted (and perhaps potentially in use). Will I be able to
restore and recover from such a dump ?

Thanks and Regards,
~aslam