The idea of being Solaris Flash Archives as a means of backing up a server is something that comes up fairly frequently - and is generally going to be a bad idea. That's not to say that you can't make it work, it's just to say that it's normally going to be the wrong answer to the problem.
Flash archives are designed for quick deployment of like servers, where like is defined in terms of the software installed, and not (necessarily) the hardware involved. By design what is "restored" from a flash archive is deliberately different to what was flashed, with many of the OS configuration files being deliberately deleted and/or re-created during the flash process. This includes things like /etc/hosts, /etc/hostname.*, /etc/netmasks, /etc/path_to_inst, the entire /dev and /devices trees and some others.
So in effect, what you put in is NOT what you get back out.
But the very definition of a backup/restore is that you get back exactly what you started with. ufsdump (or any commercial backup software) will give you a restored machine which looks exactly like what you started with.
Why does this matter?
Sure, it's possible to fix some of the files which are deliberately delete/changed (such as /etc/hosts) using post-install scripts, but to do this reliably means you need to actually take copies of these files whenever you do a flash archive, which begins to get messy.
Others like /dev and path_to_inst are a little more difficult. If you've added storage to the machine post-install (such as if you didn't have any external storage installed during the initial install) then there's a very good chance that your controller numbers will be different after the flash "restore" than they were before.
Add in network interfaces and it gets very messy (the on-board NET0 on a V440 is ce0 if you build the machine without any extra CE cards in it, but will be something like CE4 or CE8 if you've installed some extra cards afterwards).
The whole concept of backup/restore is about getting your machine back exactly as it was when the backup was taken - Flash simply doesn't give you this (and wasn't designed to).
There are a few cases where Flash can replace backups, but it's pretty much the same cases where JumpStart alone can replace backups - such where you've got a pool of similar machines where details like controller numbers aren't important and network config can be easily re-created. Desktop workstations and pools of compute servers/web servers/etc spring to mind. General purpose servers normally do not fit into this category.
Keep in mind that you can do ufsdump over a network in much the same way as you can do a flarcreate. The restore side is a little more difficult to automate, but only if you don't take into account all the "extra" stuff you need to do for flash to get things back how you started.
ufsdump 0f backuphost:/backups/myhost-root.ufs /
Or even better, add in fssnap to make sure things are consistent :
ufsdump 0f backuphost:/backups/myhost-root.ufs `fssnap -o raw,bs=/export/home,unlink /`; fssnap -d /