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asked 2017-07-03 06:24:18 -0500

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how copy on write qcow2 works?

Copy-on-write is a optimization strategy that postpones the actual copying of data until the first write to the copy. In case of Fork(), creates an exact copy of a process, including all its memory. The fork() call doesn't actually copy any memory. Instead, it tells the kernel to trap any attempt to modify memory and copy the corresponding memory pages only when either a child or a parent process attempts to modify them.

I am not able to understand how in case of images copy on write works? I know the image will be copied to compute node while launching the instance. Is it copy on write in case of images means "if we launch multiple instances using particular image, will not create multiple copies of image until unless we save data in the instance"?

please help me to understand correctly?

how copy on write qcow2 works?

Copy-on-write is a optimization strategy that postpones the actual copying of data until the first write to the copy. In case of Fork(), creates an exact copy of a process, including all its memory. The fork() call doesn't actually copy any memory. Instead, it tells the kernel to trap any attempt to modify memory and copy the corresponding memory pages only when either a child or a parent process attempts to modify them.

I am not able to understand how in case of images copy on write works? I know the image will be copied to compute node while launching the instance. Is it copy on write in case of images means "if we launch multiple instances using particular image, will not create multiple copies of image until unless we save data in the instance"?

please help me to understand correctly?