Overlaybd

Overlaybd (overlay block device) is a novel layering block-level image format, which is design for container, secure container and applicable to virtual machine. And it is an open-source implementation of paper DADI: Block-Level Image Service for Agile and Elastic Application Deployment. USENIX ATC’20”.

Overlaybd is based on PhotonLibOS, which is a high-efficiency LibOS framework.

Overlaybd has 2 core component:

Overlaybd is a block-device based image format, provideing a merged view of a sequence of block-based layers as a virtual block device. The LBA lookup algorithm employs a linearized B+ tree and AVX-512 to optimize performance, significantly accelerating search speed up to 10X. Lookup Performance
Zfile is a compression file format which support seekalbe online…