I’ve been running an HP ProDesk 600 G4 mini (i5-8500T, 32 GB RAM) for a few years now and am very happy. I bought it with 8 or 16 GB RAM and a 256 GB M.2 for 140 €. It can fit one 2.5" SATA drive and two M.2 2280 drives. I have it running 24/7/365 with 2x2 TB M.2 SSDs and a 256 GB boot SSD and it usually uses around 7 Watts.
If you want to go the HP route, ProDesk 600 and EliteDesk 800 have two M.2 slots, while the ProDesk 400 only has one.
Alternatively, Lenovo and Dell also have similar formfactor PCs, but I don’t remember their names.
Performance wise, the 8th gen i5 is more than fine for TrueNAS and 10-15 docker containers.
I’ve been running an HP ProDesk 600 G4 mini (i5-8500T, 32 GB RAM) for a few years now and am very happy. I bought it with 8 or 16 GB RAM and a 256 GB M.2 for 140 €. It can fit one 2.5" SATA drive and two M.2 2280 drives. I have it running 24/7/365 with 2x2 TB M.2 SSDs and a 256 GB boot SSD and it usually uses around 7 Watts.
If you want to go the HP route, ProDesk 600 and EliteDesk 800 have two M.2 slots, while the ProDesk 400 only has one.
Alternatively, Lenovo and Dell also have similar formfactor PCs, but I don’t remember their names.
Performance wise, the 8th gen i5 is more than fine for TrueNAS and 10-15 docker containers.