Sheepdog is a distributed storage system for QEMU, iSCSI clients and RESTful services. It provides highly available block level storage volumes that can be attached to QEMU-based virtual machines. The volumes can also be attached to other virtual machines and operating systems run on baremetal hardware if they support iSCSI protocol. Sheepdog scales to several hundreds nodes, and supports advanced volume management features such as snapshot, cloning, and thin provisioning. Stuff like volumes, snapshots, QEMU's vm-state (from live snapshot), even ISO files can be stored in the Sheepdog cluster.