TrueNAS / FreeNAS / ZFS Storage Servers

TrueNAS Scale (Linux-based) and TrueNAS Core (FreeBSD-based) are the leading open-source NAS platforms, both built on ZFS. They scale from 4-bay SOHO appliances to multi-PB enterprise deployments. We stock IT-mode-flashed servers ready for ZFS deployment.

Critical TrueNAS hardware requirements: ECC RAM (ZFS checksums catch silent corruption, but ECC catches RAM-level corruption that ZFS can't see), HBA controllers in IT-mode (not hardware RAID — ZFS expects raw disk access), and SLOG / L2ARC devices for write-acceleration and read-cache respectively.

Recommended platforms: Dell PowerEdge R740xd (24 LFF + 4 SFF rear) or HPE ProLiant DL380 Gen10 (12 LFF or 24 SFF). Pre-flash the HBA (LSI 9300-8i, 9305-16i, or Dell HBA330) to IT-mode firmware so ZFS sees individual disks. We do this for free on request.

Storage layout: most production ZFS pools use RAID-Z2 (dual parity) for 8-12 disk vdevs, or stripe of mirrors (RAID-10 equivalent) for performance-critical workloads. Add a fast SLOG (Optane DC P5800X, Samsung PM1735) for sync-write acceleration and L2ARC (lots of cheap SSD) for read-cache.

Frequently Asked Questions

Do I need ECC RAM for TrueNAS?

Strongly recommended — not strictly required but ECC is the only way to catch RAM-level bit-flips before they reach ZFS. Without ECC, a corrupt RAM bit during write can checksum-verify on disk (ZFS sees the corrupt data) and propagate the corruption permanently. All our TrueNAS-ready servers ship with ECC DDR4 RDIMM.

What is the difference between TrueNAS Scale and Core?

TrueNAS Scale = Debian Linux-based, KVM virtualization, Docker / K8s app store, ZFS, Gluster, scaling-out clustering. TrueNAS Core = FreeBSD-based, jails for app isolation, ZFS, mature and stable. Scale is the active development focus going forward; Core remains supported.

How much memory does TrueNAS need?

Minimum 8 GB. Recommended formula: 1 GB ZFS overhead + 1 GB per TB of pool capacity. So a 50 TB pool wants ~50 GB RAM. For deduplication workloads add another 5 GB per TB of unique data — dedup is RAM-expensive. 128 GB is typical for production TrueNAS servers.

Can I expand a ZFS pool by adding drives?

Yes, but with caveats — you can add an additional vdev (a new RAID-Z group) to grow the pool, but you cannot expand an existing vdev in-place by adding drives (until ZFS 2.x RAIDZ expansion arrives, which is still maturing as of 2026). Plan vdev sizing upfront.

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