I have installed 2 x 1 TB NVMe SSDs in my Truenas scale system. The purpose it to speed up access to plex. I understand that the reason it is so sluggish is because it is accessing the config files on an NFS drive. However, in asking chatgpt, it is suggesting I make a mirror special VDEV that would then be used to speed lots of things up in addtion to plex. I just found out there is also something called a SLOG which I know nothing about. Anyway I appreciate any suggestions on how to go about using these drives most effectively. Thanks.
There is a bit to unpack with this one. In simple terms, for read cache you simply add more RAM to the system. For write cache you need a special fast drive like an intel optane.
As for the metadata drive. This should only be used if you cannot upgrade RAM or adjusting tunables.
If I had to take a wild guess, I bet it isn’t fast access to your media, I bet you are running into transcoding problems with plex. So you might want to invest in a graphics card.
That’s a good point about transcoding—Plex performance issues often trace back to that rather than pure disk speed. But if metadata is stored on slower storage like NFS, adding a special VDEV with NVMe still might help reduce latency, especially for directory-heavy workloads.