Introduction
One of the most frequently debated topics in enterprise storage is whether to use a hardware RAID controller or an HBA (Host Bus Adapter) in IT Mode. The answer depends entirely on your operating system and storage architecture — and getting it wrong can lead to data loss, poor performance, or incompatibility.
This guide cuts through the confusion and gives you a clear decision framework for ZFS, TrueNAS, Proxmox, VMware, and Windows Server environments.
The Core Difference
The fundamental difference between an HBA and a RAID controller comes down to who manages the drives:
- HBA (IT Mode): The card passes drives directly to the OS. The OS sees each physical drive individually and manages storage in software.
- RAID Controller: The card manages drives in hardware, presenting logical volumes (virtual disks) to the OS. The OS sees only the RAID volume, not the individual drives.
When to Use an HBA
Use an HBA in IT Mode when your OS or storage platform manages storage in software:
- TrueNAS (CORE or SCALE): ZFS requires direct access to physical drives. Never use a hardware RAID controller with ZFS — it prevents ZFS from detecting drive failures and performing self-healing.
- Proxmox with ZFS: Same rule applies. Use an HBA so Proxmox ZFS can see and manage each drive directly.
- Linux with mdadm or ZFS: Software RAID requires raw drive access.
- JBOD expansion: Connecting a JBOD shelf to a server requires an HBA, not a RAID controller.
Recommended HBA cards: LSI 9300-8i, 9300-16i, 9400-8i, 9500-8i, 9500-16i (all in IT Mode firmware).
When to Use a Hardware RAID Controller
Use a hardware RAID controller when the OS should not manage storage directly:
- Windows Server: Hardware RAID simplifies storage management and provides cache-backed write performance with BBU or CacheVault protection.
- VMware ESXi: Hardware RAID presents a clean logical volume to the hypervisor, simplifying datastore management.
- Legacy applications: Some enterprise applications expect hardware RAID and do not support software-defined storage.
- High write workloads: RAID controllers with onboard cache (2GB–4GB) and CacheVault protection deliver significantly higher write IOPS than software RAID.
Recommended RAID controllers: Broadcom MegaRAID 9361-8i, 9460-8i, 9500-16i, 9560-16i.
The IT Mode Firmware Requirement
Many LSI HBA cards ship with IR (Integrated RAID) firmware from the factory. For ZFS and TrueNAS use, you must flash the card to IT Mode firmware, which disables the onboard RAID engine and enables pure pass-through operation.
At Zhongxin Data, all HBA cards sold for JBOD/ZFS use are pre-flashed to IT Mode firmware unless otherwise specified. Always confirm firmware mode when ordering.
Tri-Mode Controllers: A Middle Ground
Modern Broadcom Tri-Mode controllers (9400-8i, 9500-16i, 9560-8i) can operate in both RAID and HBA modes depending on firmware configuration. They also support NVMe drives alongside SAS and SATA — making them ideal for mixed storage environments.
Quick Decision Guide
- TrueNAS / ZFS: HBA in IT Mode — always
- Proxmox ZFS: HBA in IT Mode — always
- VMware ESXi: Hardware RAID controller (MegaRAID)
- Windows Server: Hardware RAID controller (MegaRAID)
- Mixed NVMe + SAS/SATA: Tri-Mode controller (9500-16i or 9560-16i)
- JBOD expansion: HBA in IT Mode
Shop HBA and RAID Controllers at Zhongxin Data
Zhongxin Data stocks a full range of Broadcom MegaRAID RAID controllers and LSI HBA cards in IT Mode. All hardware is original OEM, fully tested, and firmware-verified before shipment. Worldwide shipping from Hong Kong with warranty included.
Contact us for bulk pricing or firmware configuration questions.