LVMCache: Why use a cachepool instead of a cachevol?

Question

I'm aware of the differences between a cachepool and cachevol.

Cachepool separates the cache data and metadata into two separate volumes, whereas a Cachevol uses a single volume for both.

My question is, what is the benefit of using a cachepool instead of just using a cachevol? The only scenario I can think of that it would make the most sense would be if you wanted to dedicate a single device (or single set of devices) to the cache's metadata, and a separate device (or set of devices) for the actual cache data. But that seems like a very specific scenario, and it also doesn't address the question of Why?

Why do most people default to using a cachepool instead of a cachevol, esp. when one device is used for caching?

What is the motivation/pros-cons to using a cachepool vs cachevol?

Answer 1

From my limited perspective, there really isn't a reason for everyone to be using a cachepool, and it's the result of blindly following enterprise tutorials for the sake of it.

Outside of using a separate physical drive for metadata and a separate physical drive for data, for the sake of improving throughput, I can't find much justification for using a cachepool. If you're only using a single SSD for caching (which, I would assume is the vast majority of desktop users), it seems that a cachevol is more than sufficient.

And, it potentially maximizes your caching ability. Rather than having a reduced cache size for data in order to allow room for the metadata, you can leave that up to LVM and allocate the entire device as a cachevol.

It seems like the only reason for a cachepool is for caching using two or more SSDs.