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When performing [[incremental dumps]] or [[iterative migration]], a layered stack of memory images is created. In that stack, some data is duplicated (i.e. same memory page is present in multiple images). This article describes ways to deduplicate such data by punching holes in image files (using <code>fallocate()</code> syscall with <code>FALLOC_FL_PUNCH_HOLE</code> flag).
Two ways to deduplicate memory images are available.
== Deduplication action ==
The <code>criu dedup</code> command opens the image directory and punches holes in the ''parent'' images where ''child'' images would replace them.
== On the fly deduplication ==
The <code>--auto-dedup</code> option can be used for <code>criu dump</code> and <code>criu page-server</code>. It causes every write to images with process' pages to punch holes in the respective parent images.
The option is extremely useful in [[disk-less migration]] scenario.
== See also ==
* [[Iterative migration]]
* [[Incremental dumps]]
* [[Disk-less migration]]
* [[Page server]]
[[Category: Memory]]
[[Category: Images]]
Two ways to deduplicate memory images are available.
== Deduplication action ==
The <code>criu dedup</code> command opens the image directory and punches holes in the ''parent'' images where ''child'' images would replace them.
== On the fly deduplication ==
The <code>--auto-dedup</code> option can be used for <code>criu dump</code> and <code>criu page-server</code>. It causes every write to images with process' pages to punch holes in the respective parent images.
The option is extremely useful in [[disk-less migration]] scenario.
== See also ==
* [[Iterative migration]]
* [[Incremental dumps]]
* [[Disk-less migration]]
* [[Page server]]
[[Category: Memory]]
[[Category: Images]]