i want to migrate sun box 5.8 to 5.10 and also 5.9 to 5.10 with jump start
without ditrubing any users, how it can be done?
I assume you do know how to set up a jumpstart server, don't you?
Can the machines be rebootet?
Back up machine
upgrade server
restore userdata
or did you want to do that online? 
ya i want to do it online
it can't be done online... you need a reboot to start the new os version...
you can use "liveupgrade" to minimize the downtime:
Known, but underused Solaris Features: Live Upgrade - c0t0d0s0.org