devel/migration/CPR.rst

8 cpr-reboot is the only available mode.
13 guest block devices between quitting old QEMU and starting new QEMU.
18 cpr-reboot mode
19 ---------------
23 resumes by running QEMU with the ``-incoming`` option.  Because the
27 Guest RAM can be saved in place if backed by shared memory, or can be
37 guest in the suspended runstate, such as by issuing the
38 ``guest-suspend-ram`` command to the QEMU guest agent.  The agent
39 must be pre-installed in the guest, and the guest must support
47 It is recommended that guest RAM be backed with some type of shared
48 memory, such as ``memory-backend-file,share=on``, and that the
49 ``x-ignore-shared`` capability be set.  This combination allows memory
50 to be saved in place.  Otherwise, after QEMU stops the VM, all guest
54   * Set the migration mode parameter to ``cpr-reboot``.
55   * Set the ``x-ignore-shared`` capability if desired.
58     provided the command captures all the data from the outgoing side,
59     and provides all the data to the incoming side.
63   * Start QEMU with the ``-incoming defer`` option.
64   * Set the migration mode parameter to ``cpr-reboot``.
65   * Set the ``x-ignore-shared`` capability if desired.
66   * Issue the ``migrate-incoming`` command.
74   # qemu-kvm -monitor stdio
75   -object memory-backend-file,id=ram0,size=4G,mem-path=/dev/dax0.0,align=2M,share=on -m 4G
80   (qemu) migrate_set_parameter mode cpr-reboot
81   (qemu) migrate_set_capability x-ignore-shared on
82   (qemu) migrate -d file:vm.state
92   # qemu-kvm ... -incoming defer
95   (qemu) migrate_set_parameter mode cpr-reboot
96   (qemu) migrate_set_capability x-ignore-shared on
105   # qemu-kvm -monitor stdio
106   -object memory-backend-file,id=ram0,size=4G,mem-path=/dev/dax0.0,align=2M,share=on -m 4G
107   -device vfio-pci, ...
108   -chardev socket,id=qga0,path=qga.sock,server=on,wait=off
109   -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0
115   # echo '{"execute":"guest-suspend-ram"}' | ncat --send-only -U qga.sock
119   (qemu) migrate_set_parameter mode cpr-reboot
120   (qemu) migrate_set_capability x-ignore-shared on
121   (qemu) migrate -d file:vm.state
131   # qemu-kvm ... -incoming defer
134   (qemu) migrate_set_parameter mode cpr-reboot
135   (qemu) migrate_set_capability x-ignore-shared on
146 cpr-reboot mode may not be used with postcopy, background-snapshot,