Solaris

If I do ldm ls l ldom1 the memory block is as follows:-

Code:

MEMORY
    RA               PA               SIZE
    0x20000000       0x20000000       64G
    0x1420000000     0x1020000000     16G
    0x1c20000000     0x1420000000     16G
    0x2420000000     0x1820000000     16G
    0x2c20000000     0x1c20000000     6G

What are RA/PA? What is total memory allocated? Why split like this?

Memory is split probably due to adding and removing memory from virtual machine, to other virtual machines etc.
They system/hypervisor will try it's best to satisfy your additional memory request with continuous memory space, if possible, if not it will give you free memory present on the system.

PA is physical addresss, as for RA i'm not sure

The LDOM itself will see the cumulative value of those present, 118 GB.

You can check that from the ldom itself via :
echo "::memstat" | mdb -k

Hope that helps
Regards
Peasant.