Difference between revisions of "Incremental dumps"

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If you're doing several dumps in a row, the 2nd and subsequent dumps can be speed up. Here's how:
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{{FIXME|describe why incr. dumps are needed, and when to use pre-dump ([[iterative migration]]) instead of incr. dumps.}}
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If you're doing several dumps in a row, the 2nd and subsequent dumps can be sped up. Here's how:
  
 
== Create the first dump ==
 
== Create the first dump ==
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  # mkdir <path-to-images>/N/
 
  # mkdir <path-to-images>/N/
  # criu dump --tree <pid> --images-dir <path-to-images>/N/ --prev-images-dir ../N-1/
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  # criu dump --tree <pid> --images-dir <path-to-images>/N/ --track-mem --prev-images-dir ../N-1/
  
 
* No <code>--leave-running</code> option will make tasks be killed after dump;
 
* No <code>--leave-running</code> option will make tasks be killed after dump;
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  # criu restore --images-dir <path-to-images>/ANY/
 
  # criu restore --images-dir <path-to-images>/ANY/
  
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{{Note|After each (but the last) dump tasks continue running and thus can modify filesystem. CRIU does not snapshot filesystem and assumes, that proper filesystem state for restore is provided by a user.}}
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== Data deduplication ==
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See [[memory images deduplication]].
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== See also ==
  
{{Note|After each (but the last) dump tasks continue running and thus can modify filesystem. CRIU doesn't snapshot filesystem and assumes, that proper filesystem state for restore is provided by user}}
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* [[Live migration]]
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* [[Disk-less migration]]
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* [[Iterative migration]]
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* [[Memory images deduplication]]
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* [[Page server]]
  
 
[[Category:HOWTO]]
 
[[Category:HOWTO]]
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[[Category:Memory]]

Latest revision as of 04:21, 31 August 2016

Tools-spanner-hammer.svg FIXME: describe why incr. dumps are needed, and when to use pre-dump (iterative migration) instead of incr. dumps.

If you're doing several dumps in a row, the 2nd and subsequent dumps can be sped up. Here's how:

Create the first dumpEdit

# mkdir -p <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 dumpEdit

# 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 dumpEdit

# mkdir <path-to-images>/N/
# criu dump --tree <pid> --images-dir <path-to-images>/N/ --track-mem --prev-images-dir ../N-1/
  • No --leave-running option will make tasks be killed after dump;
  • No need in memory tracking option.

RestoreEdit

Now you can restore the processes from whatever images you want

# criu restore --images-dir <path-to-images>/ANY/
  Note: After each (but the last) dump tasks continue running and thus can modify filesystem. CRIU does not snapshot filesystem and assumes, that proper filesystem state for restore is provided by a user.

Data deduplicationEdit

See memory images deduplication.

See alsoEdit