Is it possible to 'Hibernate' a Solaris server?

I need to physically move a server running Solaris to a new location. If I power off the machine and restart it, I would manually need to check if all the required process are running.

Is there any way I can hibernate the machine so that it would just restore its state when I power it on again?

Depends on the machine - Solaris on some SPARC systems supports suspend-to-disk via the sys-suspend command, but Solaris on x86/x64 systems does not.

See if you can find the sys-suspend command alanc mentioned above (test it out on another system if possible).

Alternatively a workaround would be to do a 'ps -ef' listing on the currently running processes on the server. Shutdown, move and restart the system and compare the 'ps' output once you've restarted the server to make sure the same set of processes are running once more. (They will obviously be running under different process id's.)

For a more verbose listing of the full commands that are running you could do

/usr/ucb/ps -auxwww

which gives the full process command line with parameters and may be more helpful.