Patent ID: 8065737

Claim:
A system for virus scanning boot images for a plurality of compute nodes, comprising: a first storage unit for storing blocks of a root image of said compute nodes; a plurality of second storage units for storing leaf images of respective compute nodes, said leaf images only comprising: additional data blocks not previously contained in said root image; and changes made by respective compute nodes to the blocks of said root image; and a plurality of union block devices corresponding to said compute nodes, said union block devices for interfacing between said compute nodes and said first and second storage units to distribute said boot images to said compute nodes, wherein said union block devices create said boot images by merging the blocks of said root image stored on the first storage unit with the blocks of respective leaf images stored on respective second storage units, wherein said boot images each comprise portions of said root image and said blocks of respective leaf images for said respective compute nodes, and wherein further at least one of said union block devices is operable to allow a particular compute node to scan said root image for viruses and notify another of said compute nodes that said scanning of said root image has been performed.