Proxmox + TrueNAS + 10GbE - VM Storage Performance Much Lower Than Expected

Hello, I’m in the process of refining my home lab setup and I’ve hit a performance issue that I can’t quite explain. Current layout: * Host: Ryzen 7 5700X, 128GB DDR4 ECC UDIMM * Motherboard: B550 chipset * Hypervisor: Proxmox VE 8.x * Storage HBA: LSI 9300-8i (IT mode) * Pool: 6× 8TB SATA HDD (RAIDZ2) * Cache: 2× NVMe (mirrored, used as special device + metadata) * Network: Mellanox ConnectX-3 10GbE (direct attach) TrueNAS SCALE is running as a VM under Proxmox. The HBA is passed through via PCIe passthrough (IOMMU enabled, no grouping issues). TrueNAS pool health is good, no SMART errors. The issue: When testing directly inside the TrueNAS VM (local pool), I see expected sequential speeds (900–1000 MB/s read, 600–700 MB/s write). However, when accessing the same storage over SMB from another 10GbE machine, I’m only getting 350–400 MB/s reads and 250–300 MB/s writes. Things I’ve already checked: * MTU 9000 enabled on both ends * Verified 10Gb link is... Read more