Does anyone know the difference between a Logical Domain and a Container ?
Both seem to be virtualisation technologies from Sun.
Also I know a Domain can have containers within it but I don't see the point
ldom is a per prozessor virtualisation... containers is a software (solaris) virtualization. you can use zones/containers on all solaris 10 (sparc and x86) installations but you need special hardware to use ldoms!
It is not "per processor" virtualization, as you can split a processor/core/threads into different domains, and still you create the LDOMs through software..
It'd take too much typing to properly explain the difference...
...in a nutshell,
LDOMs allow you to assign your hardware to different virtual hosts for exclusive use. Say you have a T5220 with an 8-core CPU. You could create 8 LDOMs and assign a core to each. Each core will be for the exclusive use of the domain you assigned it to, regardless of the load on the other domains. With zones/containers, all zones can use any CPU core/thread that they need when they need it. Limits can be set as far as how much CPU they use, but you cannot specify which CPU/core/thread they are to use.
With LDOMs you get an OBP per domain that can be configured independently from the others. Zones don't have OBPs.
You can "brand" a zone as a Solaris 8 or Solaris 9 zone (and I understand RHEL as well), running an instance of either OS on top of Solaris 10. This is useful in those cases when you are refreshing hardware but app vendors only support their apps on the older OSs. You can't "brand" an LDOM, but you can create a branded zone inside an LDOM.
Root on the global zone can see all of the file systems on each zone.
Root on the primary domain cannot see the files systens on the domains.
I hope this gives you a better idea.
nice... thats the long story. i didn't had time to be so exact 
one thing:
branded zones can be linux (rhel) and solaris 8 not 9 (afaik).
As you wrote earlier, logical domains can be bound to core thread level so you can actually create up to 64 LDoms on that box.
Each one can run either Solaris or Ubuntu which is certified on LDoms.