Presented at Storage Developer Conference (SNIA SDC 2016):
The seismic shift
Fact is, NAND media is inherently not capable of executing in-place updates. Instead, the NAND device (conventionally, SSD) emulates updates via write + remap or copy + write + remap operations, and similar. The presence of such emulation (performed by SSD’s flash translation layer, or FTL) remains somewhat concealed from an external observer.
Other hardware and software modules, components and layers of storage stacks (with a notable exception of SMR) are generally not restricted by similar intervention of one’s inherent nature. They could do in-place updates if they’d wanted to.
Nonetheless, if there’s any universal trend in storage of the last decade and a half – that’d be avoiding in-place updates altogether. Circumventing them in the majority of recent solutions. Treating them as a necessary evil at best.