Fix: Poor SMB performance and High CPU for TrueNAS scale on Proxmox

Hi all,
writing this post just for others to not run into the same issue like I had:

Scenario:

  • running TrueNAS Scale on Proxmox host (Intel N100 based mini-PC)
  • Setup as per recommendations with 12 GB RAM, 4 CPU, VirtIO SCSI
  • Single Pool, compression and other highly demanding features off

Symptoms:

  • When writing to SMB shares, CPU was going to 100%
  • Write speed starting at 120MB/s and after few seconds going down to 50MB/s

Fix:

  • Enabled IOMMU on Proxmox Host (Forum does not let me put a link, but you´ll find how)
  • Change CPU Type of TrueNAS VM to “host” (was x86-64-v2-AES before)

Now I´m running at full speed with 30% CPU load