Features/Migration

From QEMU

Summary

Migration roadmap.

Owner

  • Name: Juan Quintela
  • Email: quintela@redhat.com

Detailed Summary

This page describes what are the changes planned for migration and who is supposed to do each of the changes.

Status

This is the roadmap, features are integrated upstream as they are done.

TODO Short Term

  • use TLS for communication (Orit)

Right now all migration communication are done through clear channels. If you need to encrypt the channel, you need to use an external program. The problem with this is the performance loss. We need to transfer all data to another program, and then to the network.

  • Improve migration bitmap handling (Juan)

We have a dirty bitmap that has 8 bits for each page. But we only use three of them (MIGRATION, VGA and CODE). CODE is only needed for TCG, KVM only cares about MIGRATION, and VGA only is needed for VGA frame bufferes. Idea is to split this bitmap in three smaller ones that are only used/allocated when needed. This is specially important when the RAM size of the guest is very big.

  • Improvements in migration performance (Juan, Paolo)

Remove last performance problems. Migration code has already moved to a thread. We are removing all the extra copies.

  • Migration native over infiniband?

Study.

TODO Long Term

  • Add size + checksum to sections. This is one incompatible change and needs further thought.
  • Make embedded sections real sections, with headers. This will allow us to version internal state.
  • Unit testing. In colaboration with qdev, allow devices to be tested alone with old/new migration versions/subsections.
  • define target machine from the monitor. This will allow us to migrate the configuration of the machine from source to destination, instead of having to had an identical command line in both places.

Code

The code still not merged is currently kept in several branches of this git repository: