Hi!
I am quite new to Solaris and come from AIX world.
I need to clone running production LDOM. In AIX you just take mksysb and restore it to new LPAR. It will install with blank network settings.
How to do it in Solaris 11? Can't find document to clone from running system.. they talk only about Golden images..
LDOM OS disks are installed in separete LUN's from storage.
Use "Unified Archives". They allow you to clone an existing running system, including one that has non global zones, to another system.
See https://blogs.oracle.com/maineoffice/entry/introducing\_unified\_archives\_in_solaris and Using Unified Archives for System Recovery and Cloning in Oracle Solaris 11.2
Thanks for quick answer. But it seems customer has Solaris 11.1 and Sparc T5-4, so this maybe doesn't work?
UAR are indeed supported from 11.2 onwards but with a couple of commands, a 11.1 system will be running Solaris 11.2:
# pkg update --accept
# init 6
Yeah, I definetly agree those should be upgraded, but at this moment is not possible, not up to me.
Any advice for doing it in 11.1? We can have break for that server..
dd, zfs snapshot, ufsdump, flar, unified archive, TAR?
I am little confused 
Have you tried adding a another same disk to existing rpool mirror, then after that using zpool split feature ?
According to the documentation, it should be available on solaris 11.1
https://docs.oracle.com/cd/E26502_01/html/E29007/gayrd.html\#gjooc
A mirrored ZFS storage pool can be quickly cloned as a backup pool by using the zpool split command. You can use this feature to split a mirrored root pool, but the pool that is split off is not bootable until you perform some additional steps.
If you have other zpools on that LDOM, you will need to do the same with them.
I would advise tho, not to have network active on the new LDOM you are importing the split ed rpool, due to IP and other enviroment specific information is not changed.
After you get it to boot, change the ip address, hostname for your new environment, then add vnets and reboot.
I'm unable to find in documentation these additional steps mentioned tho, but you can try it and see what errors you get (on test ldoms).
If you have unsolvable problems, i will try the method myself to see if any problems exist and get back to you, but i leave the first fun for you 
Please note that it is not an upgrade but a simple update. Solaris 11 is quite different from Solaris 10 in this area (and some others ...)
Updating Solaris 11 is a very low risk operation given the fact you can easily rollback to the previous version with a single reboot should something doesn't work as expected.
Nothing straightforward. Peasant already answered to that. A splitted ZFS root pool is the closer but has some pitfalls.