strange backup issues
 

Hello,
I would like to know if there is a way to make a snapshot of the
entire system (in runtime)to backup it and restore it after a crash.
I would like to know if anybody can point me to some documentation about
backup issues in general, to know if to this way (that was suggested
me by the proprietary of the linux box), could be preferable a
classic solution that use tar on the directories that interest.
Thanks,
tano

I recommend you read this as a starting point. It should get you started on your "Bare Metal Recovery" learning pathway.

Thanks, I will read it!

You might also want to look at mkcdrec, or mondoarchive. They excel at this, and let you create bootable ISO's, suitable for CD-ROM/DVD restoration.

Ok, ok! I will look at both packages. But what about a paper that describe when is
convenient to backup via system snapshow and when the backup politic could be to
save only the dirs you want?

Not sure what you're saying. You have to figure out when is a good time to back your systems up, no one can tell you that. You'll also have to read the documentation for those packages, and find out how to use them.

Ok, I will tell you. On a server in which running 3 xen virtual machines with windows xp virtualized and samba, the server owner ask me to do a snapshot backup. I think that
backup only the virtual machines image files and samba dir could be a good thing, but
he has to reply that restoring the system could be a slow task in this way, so I would
like to view some 'case studies' or examples and make an opinion when I will have to
do a server by myself :-)