Lazy transmission of memory pages during checkpointing

A non-transitory computer readable medium comprising instructions to be executed in a first host computer to cause the first host computer to carry out a method of transmitting to a second host computer, modifications made to memory pages of a virtual computing instance running in the first host computer during a time interval, wherein the method comprises:

• stunning the virtual computing instance at the end of the time interval;
• while the virtual computing instance is stunned, detecting at the first host computer the memory pages that have been modified during the time interval, and copying one or more of the modified memory pages to a memory region in the first host computer, wherein the modified memory pages include first memory pages and second memory pages and the first memory pages are the one or more memory pages copied to the memory region;
• resuming the virtual computing instance;
• and
• after said resuming, transmitting the first memory pages from the memory region in the first host computer to the second host computer while the virtual computing instance is running in the first host computer and transmitting modifications of the second memory pages from the memory region in the first host computer to the second host computer while the virtual computing instance is running in the first host computer, wherein the first memory pages are modified memory pages in each of which an amount of modifications is determined to exceed a threshold amount and modified memory pages not having a previous version thereof stored in the memory region, and the second memory pages are modified memory pages in each of which an amount of modifications is determined to not exceed the threshold amount.

A computer system configured to transmit modifications made to memory pages of a virtual computing instance running therein to a backup computer system, the computer system comprising:

• a system memory comprising a hypervisor component configured to instantiate the virtual computing instance;
• and
• a processing unit configured to execute the hypervisor component to transmit modifications made to the memory pages of the virtual computing instance during a time interval by performing the steps of:
• stunning the virtual computing instance at the end of the time interval;
• while the virtual computing instance is stunned, detecting the memory pages that have been modified during the time interval, and copying one or more of the modified memory pages to a memory region in the system memory, wherein the modified memory pages include first memory pages and second memory pages and the first memory pages are the one or more memory pages copied to the memory region;
• resuming the virtual computing instance;
• and
• after said resuming, transmitting the first memory pages from the memory region in the system memory to the backup computer system while the virtual computing instance is running and transmitting modifications of the second memory pages from the memory region in the system memory to the backup computer while the virtual computing instance is running, wherein the first memory pages are modified memory pages in each of which an amount of modifications is determined to exceed a threshold amount and modified memory pages not having a previous version thereof stored in the memory region, and the second memory pages are modified memory pages in each of which an amount of modifications is determined to not exceed the threshold amount.