Hello all, I just joined today. I have owned NAS units before, so I am not a complete rookie. 
I just purchased a new DS 1821+ and would like suggestions on how to get the best performance out of it. This is what I have. I have six hard drives. Two are 12TB, and the other four are 10TB. I have two NVMe 1TB each for cache. I have two 1TB SSD, which I can place in drive bays 7 and 8 if needed. I am using an 8-port 2.5 network switch and waiting for the 10-gig NIC card to arrive. I will also be installing 32 gigs of memory. The following is how the unit will be used. I will use the Active backup for business to backup one MAC and three PCs. I will use Adobe Lightroom for Photography work. My Lightroom catalog will be connected to my MAC by SSD, and I will use Synology Photos for family access. Plex server for music and movies. When in use, I will run an Ubuntu VM and one Minecraft container for the kids. I forgot I stored my documents in a shared folder on the NAS, not the computer. My question is: Is the cache read-only or read-write? Hard drive, one pool, one Volume, or another setup.