Incremental dumps

If you're doing several dumps in a row, one in some time after another, the 2nd and subsequent dumps can be speed-ed up and that's how

Create the first dump

# mkdir <path-to-images>/1/
# criu dump --tree <pid> --images-dir <path-to-images>/1/ --leave-running --track-mem

• Images are put into the 1/ sub-directory, since we're about to create the 2nd (and more) incremental dumps and it's handy to store them in this way;
• The --leave-running option is used to make criu not kill the tasks after dump, but let them run further;
• The --track-mem option makes criu ask kernel to monitor memory changes to optimize the subsequent dump.

Create the second dump

# mkdir <path-to-images>/2/
# criu dump --tree <pid> --images-dir <path-to-images>/2/ --leave-running --track-mem --prev-images-dir ../1/

• Note, that the --prev-images-dir path is relative to the --images-dir one;
• Similarly the 3rd and all the other dumps can be created.

Create the last dump

# mkdir <path-to-images>/N/
# criu dump --tree <pid> --images-dir <path-to-images>/N/ --prev-images-dir ../N-1/

• No --leave-running option will make tasks be killed after dump;
• No need in memory tracking option.

Restore

Now you can restore the processes from whatever images you want

# criu restore --images-dir <path-to-images>/ANY/