Virtual machine backup

摘要

A computer system comprises a processor unit arranged to run a hypervisor running one or more virtual machines, a cache connected to the processor unit and comprising a plurality of cache rows, each cache row comprising a memory address, a cache line and an image modification flag and a memory connected to the cache and arranged to store an image of at least one virtual machine. The processor unit is arranged to define a log in the memory and the cache further comprises a cache controller arranged to set the image modification flag for a cache line modified by a virtual machine being backed up, periodically check the image modification flags and write only the memory address of the flagged cache rows in the defined log. The processor unit is further arranged to monitor the free space available in the defined log and to trigger an interrupt if the free space available falls below a specific amount.

主权项

1. A non-transitory computer program product for maintaining a backup image of a virtual machine, the non-transitory computer program product comprising:
a non-transitory computer readable storage medium having program instructions embodied therewith, the program instructions comprising program instructions to, indicate, in a log, updates to memory of a virtual machine when the updates are evicted from a cache of the virtual machine; determine a guard band for the log, wherein the guard band indicates a threshold amount of free space for the log; determine that the guard band will be or has been encroached upon indicating an update in the log; update a backup image of the virtual machine based, at least in part, on a set of one or more entries of the log, wherein the set of entries is sufficient to comply with the guard band; and remove the set of entries from the log.