Please let me know how to increase the size of rpool in solaris 11 in ldom. I know how to map the new LUN to LDOM after that please let me know the procedure to increase the rpool and how to identify new disk in OBP level of ldom as I need to set the new/lun to be my new boot device.
You safely increase it on the storage side, not add additional luns to rpool.
After you expand the lun from the storage side, issue a fabric rescan.
If you have not used slice 2 (whole disk), you will need to expand the slice via format command.
Otherwise, issue a zpool set autoexpand=on rpool inside the ldom to see the space.
If you really want to add additional lun or using local disks i would suggest presenting the bigger lun to ldom.
Using zpool attach command mirror rpool to bigger disk.
After the re-silvering is complete detach the old disk from mirror using zpool detach.
After detach issue a autoexpand from above for rpool to grow.
Remove the old disk from ldom and set boot-device variable for that ldom to point to added disk instead of smaller one.
As per you suggestion I added new bigger LUN and then attached it to mirror and after resilvering I detach the older and disk using zpool detach command. and thing went fine. Now If due to some reason I was to boot from older detach disk is it possible. I don't have any issue if my older disk can use different rpool name. For instance my, older detached original rpool disk was c0t0d0 and new mirror bigger disk is c1t2d0 which is currently using with rpool.
zpool detach is a destructive operation, so no you cannot reuse / boot that disk.
If you are using LDOM, you could just poweroff the ldom, and remove one out of two disks using ldm commands.
You should now have two identical bootable rpools.
Be sure to reconfigure your solaris instance when booted on another LDOM and remove degraded part of mirror from both operating systems.
Perhaps same can be achieved online, by using zpool offline <old disk> , followed by zpool detach <old disk> and from hypervisor ldm rm vdisk ..
You can test this using Solaris x86 and KVM, of course you will now not be using ldm commands, but create a new KVM solaris with disk you cloned with one of the techniques mentioned.
There is also an option of storage cloning techniques, just make sure those luns are never on the same LDOM.
As for links, login to My Oracle site and search for 'zpool split rpool'.
ZFS send/recv should be used to backup zfs filesystems, including rpools, while split would be second best and storage cloning as a last resort.
Everything else is hackery, do not try to reinvent the wheel.