NVMe Polishes Its Specs, Brings Virtualization to Locally Attached SSDs

The NVM Express consortium has revised its suite of NVMe specifications with new features and engineering change notices. The most noteworthy update is the addition of SSD-level virtualization, which can streamline live VM migration by maintaining storage identities across servers. This advancement, known as PCIe Exported NVM Subsystem Migration, allows locally-attached PCIe SSDs to be abstracted into host-defined virtualized NVM subsystems.

This enables virtual machine (VM) mobility without storage reconfiguration during a VM's transfer from one server to another. According to Mike Allison, a senior director at SSD manufacturer Samsung and NVM Express board member, this innovation creates a clean separation between the virtual machine's perception and the underlying hardware complexity.

A key aspect of this update is the controller-based rate limiting, voltage monitoring, and factory-reset capabilities, as well as support for post-quantum cryptography. Allison emphasizes that the host only perceives exported controllers and namespaces, eliminating interaction with physical controllers and namespaces. This virtualization enables the virtual machine manager (VMM) to rely on virtualization built into the SSD, offloading complexity from the VMM.