Object storage now has an mmap function similar to POSIX. That means the processing and scalability limitations of POSIX become the new bottleneck
"POSIX has been the standard file system interface for Unix-based systems (which includes Linux) since its launch more than 30 years ago. Its usefulness in processing data in the user address space, or memory, has given POSIX-compliant file systems and storage a commanding presence in applications like deep learning that require significant data processing. The POSIX-compliant Lustre file system, for example, powers most supercomputers, and POSIX's dominance continues down market too.
POSIX has its limits, though and features like statefulness, prescriptive metadata, and strong consistency become a performance bottleneck as I/O requests multiply and data scales, limiting the scalability of POSIX-compliant systems. That's often an issue in deep learning, AI and other data-intensive uses now, but as data and the need to analyze it grow exponentially, the problem has, over time, moved down market..."
NVMe brought super-fast flash storage to the datacentre, but it needs NVMe-oF to allow it to bring the benefits of rapid access and low latency to SAN and NAS shared storage
"It's almost a decade since the NVM Express Workgroup released the first version of the NVMe standard. Since then, the technology has become an increasingly common interface for solid state storage.
But, on its own NVMe is somewhat limited because it is a device connection best suited to in-server or directly-attached storage.
What enterprises need is to connect flash storage seamlessly over a network, to unlock performance advantages and replace conventional disk-focused SAN technology, such as iSCSI and Fibre Channel. NVMe-over-fabrics (NVMe-oF) aims to do just that..."