A zone migration transfers an existing zone or global zone into a zone on another system. The three types of zone migrations are live migration, warm migration, and cold migration.
Live and warm migration are supported only for kernel zones. A native non-global zone uses the global zone's kernel and its software packages are linked to those of the global zone, so it cannot be migrated to a different global zone unless it is first shut down.
All zone brands support cold migration.
In a cold migration, a zone is shut down on the source host and rebooted on a target host. Use cold migration for applications that provide time-critical services or applications that have a large memory footprint. Cold migration is recommended for transferring existing zones or systems.
See Chapter 7, Migrating and Converting Oracle Solaris Zones in Creating and Using Oracle Solaris Zones for more information.
In a kernel zone warm migration, the migrated zone memory state is written to disk. The zone is moved from the source host to the destination host and restarted. This zone migration type is also known as migration using suspend and resume.
For applications where live migration is not suitable, use a warm migration. A warm migration does not require a full system reboot and restart of the application while the kernel zone is running. All networking connections are lost to the zone during a warm migration, but outage times are reduced to seconds or minutes.
Some database applications can take several hours to warm up after a system reboot. A warm migration captures the database running state and significantly decreases the outage time.
For more information, see Using Warm Migration to Migrate a Kernel Zone in Creating and Using Oracle Solaris Kernel Zones.
In a kernel zone live migration, the memory state of the migrated zone is copied to the migrated guest. Live zone migration has a brief outage time that is not noticeable to most applications or end-users. Kernel zone live migration can also be used to load balance services.
Live migration is recommended for situations where downtime must be minimized and applications must remain in a running state. The migration process can have a performance impact that might negatively affect heavy workloads. In cases such as this, use warm migration or cold migration during the outage window.
Live migration during an off-peak time can be an option as well. Live migration with a quiesced application and sufficient network bandwidth can be faster than warm migration.
See Using Live Migration to Migrate a Kernel Zone in Creating and Using Oracle Solaris Kernel Zones for more information on live migration.