My current NAS is five years old. The HDDs have started dying off one at a time and the CPU is getting a little long in the tooth and light on cores (i7 7700K). So it’s time to upgrade/build a new one and migrate things over. It’s running a five HDD RaidZ2, mirrored 280GB Optane Special Vdevs, with 10Gb networking. Plex, PiHole, SMB for Windows clients, and an iSCSI zvol for a Steam library.
I have a less old i7 12700K with 64GB RAM sitting on the shelf I’m planning to use.
I’m wondering about my options with pool topology. I would like to have two mirrored HDDs holding large media files (movies mostly, for Plex). And either two 8TB SSDs mirrored or three or four 4TB SSDs holding the iSCSI zvol, Plex, and a bunch of smaller user files.
Should I create two pools, one with HDDs, one with SSDs, and have the applications running in the SSD pool, like Plex, access data from the HDD pool? And can it be done entirely through the GUI?
Is there substantially more overhead using two pools?
Would using an old 400GB Intel 750 SSD as a cache vdev for the HDDs be a terrible idea? The block size on the HDDs is going to probably be 1MB, maybe larger. Can a L2ARC cache size be limited in the GUI? The last 100GB read off the disks would probably be plenty. I don’t think I’ve used one before. There will be 64GB of RAM to go around.