Logical Domains 1.2 Administration Guide

Migrating an Active Domain

For the migration of an active domain to occur with Logical Domains 1.2 software, there is a certain set of requirements and restrictions imposed on the source logical domain, the source machine, and the target machine. The sections following describe these requirements and restrictions for each of the resource types.

Note –

The migration operation speeds up when the primary domain on the source and target systems have cryptographic units assigned.

Migrating CPUs in an Active Domain

Following are the requirements and restrictions on CPUs when performing a migration.

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:

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
    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

    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

Migrating Physical I/O Devices in an Active Domain

Virtual devices that are backed by physical devices can be migrated. However, virtual devices that have direct access to physical devices cannot be migrated. For instance, you cannot migrate I/O domains.

Migrating Virtual I/O Devices in an Active Domain

All virtual I/O (VIO) services used by the source domain must be available on the target machine. In other words, the following conditions must exist:

Migrating NIU Hybrid Input/Output in an Active Domain

A domain using NIU Hybrid I/O resources can be migrated. A constraint specifying NIU Hybrid I/O resources is not a hard requirement of a logical domain. If such a domain is migrated to a machine that does not have available NIU resources, the constraint is preserved, but not fulfilled.

Migrating Cryptographic Units in an Active Domain

You cannot migrate a logical domain that has bound cryptographic units if it has more than one VCPU. Attempts to migrate such a domain will fail.

Delayed Reconfiguration in an Active Domain

Any active delayed reconfiguration operations on the source or target hosts prevent a migration from starting. Delayed reconfiguration operations are blocked while a migration is in progress.

Operations on Other Domains

While a migration is in progress on a machine, any operation which could result in the modification of the Machine Description (MD) of the domain being migrated is blocked. This includes all operations on the domain itself as well as operations such as bind and stop on other domains on the machine.