Iridar51 :
Sorry, how exactly is this any different from caching? The general principle seems exactly the same, the only difference is that lets you use RAM for it and makes it looks nice in My Computer window.
Important to know - modern caching and tiering software doesn't move entire files to faster storage (SSD/Optane). Instead, they only move small blocks of data that are frequently accessed. The software only moves the 'difficult' bits of the file that take a while to access. (the algorithms measure how frequently the block is accessed and how difficult it is to retrieve it.)
So, you can move 50MB of a 1GB file, for instance, and radically improve the performance of the entire file. It's a force multiplier of sorts.
Caching only keeps a
copy of the blocks on the faster storage. So, our theoretical 50MB of data will exist both on the fast device and the HDD. You have two copies of all the accelerated data, so basically you lose the entire capacity of the caching drive. For instance, your volume is still only 10TB if you combine a 10TB HDD and a 1TB SSD for caching. You cannot use the capacity of the 1TB SSD for storage. It essentially vanishes.
Tiering
moves the blocks to the faster device, but deletes it from the slower one. So, our 50MB chunk of data is now only on the SSD. That means you can use the full capacity (or close to it) of the faster device. So, when you combine a 10TB HDD and a 1TB SSD you get 11TB of usable storage (give or take a few % of the faster device).
Tiering is 'simpler' from a computing perspective, so it has less CPU overhead than caching. Also, tiering doesn't move data as frequently, so it doesn't murder SSD endurance like some caching software does. These are good things.
When it comes to RAM, it is volatile, so you can't permanently store any data in it. That means you cannot tier data (move it) to the RAM. Instead, the software only caches (keeps a copy of the data).
So, Enmotus software tiers to faster storage (SSD/Optane) and caches to RAM.