Virtual machine host server apparatus and method for operating the same

A virtual machine host server, comprising:

• a virtual machine in which a guest operating system is installed and operated;
• a cache manager configured to process an open request, a close request, and an input and/or output request for a disk image file of the virtual machine, which is stored in a storage system, and to manage a boot workload map and a boot segment;
• a cache device configured to cache the boot segment;
• and
• a prefetch manager configured to prefetch the boot segment from the cache device,
• wherein, when the cache manager instructs the prefetch manager to prefetch a boot workload map, the prefetch manager configured to open a boot segment of the storage system, to check blocks to be prefetched in the boot workload map transmitted from the cache manager, to determine whether any block to be prefetched does not exist, and to terminate prefetching when it is determined that any block to be prefetched does not exist,
• wherein, when any block to be prefetched exist, the prefetch manager configured to check a storage space of a prefetch buffer, to load data in the prefetch buffer by prefetching a boot segment through consecutive reads each having a predetermined size from the storage system when any storage space exists in the prefetch buffer to calculate a position of the corresponding block in the boot segment using an order of bits set as a block accessed in booting in the boot workload map and a number of bit strings, to calculate an actual offset of the corresponding block in the disk image file of the virtual machine using the boot workload map, to read a block to be prefetched from the prefetch buffer and loads the read block in a cache through the cache manager, and to close the boot segment.