SYSTEM AND METHOD OF OPTIMIZING VM DISK DATA TRANSFER TIME FOR COLD MIGRATION BY PRELOADING PAGE-CACHE

A fast copy method and systems for virtual machine migration. Data from the source virtual machine's (VM1) root disk is read into source server's system memory, populating data of VM1's root disk into the host's server's page cache. Data from the destination VM's (VM2) root disk is read into destination server's system memory, thereby populating data of VM2's root disk into the host's page cache. A file descriptor used to read root disks of VM1 and VM2 on both source and destination servers are kept open even after reads are complete, so page cache entries are not evicted by the source and destination servers. This enables subsequent copies of VM1's root disk to the destination server to utilize the page cache on both source and destination servers, instead of reading and writing to both VM's root disks respectively, significantly reducing the time for root disk content transfer during cold migration.