Migrating Memory in an Active Domain

There must be sufficient free memory on the target machine to accommodate the migration of the source domain. In addition, following are a few properties that must be maintained across the migration:

• It must be possible to create the same number of identically-sized memory blocks.

• The physical addresses of the memory blocks do not need to match, but the same real addresses must be maintained across the migration.

The target machine must have sufficient free memory to accommodate the migration of the source domain. In addition, the layout of the available memory on the target machine must be compatible with the memory layout of the source domain or the migration will fail.

In particular, if the memory on the target machine is fragmented into multiple small address ranges, but the source domain requires a single large address range, the migration will fail. The following example illustrates this scenario. The target domain has two Gbytes of free memory in two memory blocks:

# ldm list-devices memory
MEMORY
    PA                   SIZE
    0x108000000          1G
    0x188000000          1G

The source domain, ldg-src, also has two Gbytes of free memory, but it is laid out in a single memory block:

# ldm list -o memory ldg-src
NAME
ldg-src

MEMORY
    RA               PA               SIZE
    0x8000000        0x208000000      2G

Given this memory layout situation, the migration fails:

# ldm migrate-domain ldg-src dt212-239
Target Password:
Unable to bind 2G memory region at real address 0x8000000
Domain Migration of LDom ldg-src failed