Backup NAS
My backup NAS is filled with cheap hard drives. It EATS power, so it is turned on only when it is actively backing up data. it uses an atx board with 5 pcie slots, most of which are occupied. Connected to it are a couple of HBAs that all the hard disks are attached to. The big 4u case is very expandable, it can take 18 2.5" drives and 10 3.5" drives so I'll have lots of space going forwards!
In terms of ZFS pools, there is a large raidz1 pool containing all of the 2Tb and 8Tb HDDs (a vdev for each type) that contains backup snapshots from TrueNAS NAS as well as backup disk images. I have written a script[1], that automatically turns on this server, and runs a number of ZFS replication tasks, and once they're done turns the server off again. It runs automatically 3 times a week, so the server doesn't need to be on all the time, saving power. There is another raidz1 pool for the 500Gb disks that contains a large zvol with encrypted data. Finally the 64Gb SSDs are for random VM projects on this machine.
Generally, I have been very unhappy with TrueNAS 25.04 and will be sticking with 24.10 on my main NAS for as long as possible.
In terms of NICs, the 10Gb NIC is connected directly to TrueNAS NAS to enable speedy ZFS replication, and the everything else uplinks to my main network via the 2.5Gb NIC, enabling speedy disk image backups.
Generally, the CPU and memory on this system is very overkill. There used to be a simple board with an AMD A4-5000 inside this machine, the only reason it was upgraded was to enable connecting more PCIe lanes so I could connect even more HBAs and this even more drives. Although, the beefier CPU and spare memory does give me room to play with VM projects.
Generally speaking, this system is used for experimentation and for testing changes with TrueNAS before updating on the main system.
