Alright, this thread is old, but now that I read it, I'm starting to rethink how I'm using cache.
Is it really like a one way direction? No, right?
Cache-yes will work like a buffer for everything being added to the drives? Like first it cache, than it sends to the array, and never the other way, from array to cache?
Cache-prefer will send data in both ways, right? From array to cache, from cache to array.
Also, I came here looking for another thing, I wanted to create a share to access my cache drive. Is it possible? And, to be honest, should I use cache? I think I'd rather just use the flash m.2 SATA as a disk and benefit its speeds on applications, like MySQL.
Basically, I have a media server that very rarely is used for some data processing, hence the MySQL installed.
So, most of the time it's running a Windows VM, a Linux VM and dockers for deluge, plex, sonarr and radarr. I don't need flash speed for that, except maybe for my downloads, my intern is 240 down/20 up.
I have 6x 3TB WD Red NAS and a M.2 256GB SATA drive. 16GB of RAM running on a 2600X soon to be replaced by a 2700X.