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→Checkpointing and live migration: - fix small typo
{{Main|Checkpointing and live migration}}
A live migration and checkpointing feature was released for OpenVZ in the middle of April 2006. It allows to migrate a container from one physical server to another without a need to shutdown/restart a container. The process is known as checkpointing: a CT is freezed frozen and its whole state is saved to the file on disk. This file can then be transferred to another machine and a CT can be unfreezed unfrozen (restored) there. The delay is about a few seconds, and it is not a downtime, just a delay.
Since every piece of the container state, including opened network connections, is saved, from the user's perspective it looks like a delay in response: say, one database transaction takes a longer time than usual, when it continues as normal and user doesn't notice that his database is already running on the another machine.