Main TrueNAS
25.10.7 - Goldeye, on FreeNAS mini (2015 with replacement board), 32GB ECC RAM, four 4TB WD red hard drives, two mirrored 2.5” SATA SSD boot drives.

“Internal” backup
physically-external 10 TB single HD in SATA external case, connected through internal SATA port as a replicated backup of all datasets

External backup on local network
TrueNAS 25.10.6 - Intel NUC 8GB non-ECC RAM and 2TB 2.5” spinning hard drive running as second replication target over Ethernet