HBAs and RAID controllers both connect drives, but serve different purposes. Choose wrong and you lose either performance or data protection.
When to Use Each
| Feature | HBA (IT Mode) | RAID Controller |
|---|---|---|
| Drive Presentation | Individual (JBOD) | Virtual disks (arrays) |
| Best For | ZFS, Ceph, software RAID | Hardware RAID 5/6/10 |
| Cache | None | 1-8GB with BBU |
| Performance | CPU handles parity | Controller handles parity |