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Yes. A partly faulty HBA port can produce storage errors that look like a problem with an SC847’s rear backplane. In one community-reported case, intermittent write errors in a SAS-expander JBOD were attributed to a partly bad port on an LSI SAS9206-16e running IT-mode P20.00.07 firmware. That is one user’s diagnosis—not proof of a defect in SC847 backplanes or in the HBA model generally. Read the discussion.
What the SC847 reports do—and do not—show
A partly faulty HBA port can imitate a rear-path problem
In the discussion matching this topic, the user reported intermittent write errors against drives in a SAS-expander JBOD. The troubleshooting included ZFS status output showing write errors and a degraded test pool. The user ultimately attributed the errors to a “mostly good, but partly bad port” on an LSI SAS9206-16e HBA running IT-mode P20.00.07 firmware. This is a useful example of an HBA problem being mistaken for a rear-path fault, but it was not a controlled test or a measure of how often the problem occurs.
Rear drives missing does not confirm a bad rear backplane
A separate SC847 owner reported that front drives appeared while rear drives did not. In the captured Unraid discussion, swapping cables, trying a second HBA, and checking power did not resolve the symptom; a backplane fault remained a hypothesis, not a confirmed diagnosis. See the Unraid discussion.
Load-related resets have more than one possible cause
In another community report, an LSI 9500-16i reset and missing backplanes appeared during ZFS scrubs. Contributors discussed checking cables and topology and monitoring HBA temperature, but the discussion excerpt does not establish a definitive cause or a temperature limit. A symptom that appears during heavy I/O is a reason to reproduce the condition and preserve logs—not enough by itself to condemn the HBA or backplane. See the TrueNAS discussion.
#1 Best Overall
- Compatible with: LSI 9300-8i; Controller: LSI/Broadcom SAS3008 (12Gb/s SAS)
- Firmware (FW): HBA IT Mode (Non-RAID); Data Transfer Rate: up to 12Gbps SAS, SATA 6Gbps
- Host Interface: PCIe 3.0 x8; Internal Connectors: 2× Mini-SAS HD SFF-8643. --Direct attach up to 8 drives, and expand via external SAS Expander for large arrays
- PERFECT FOR: ZFS, FreeNAS/TrueNAS, unRAID, Proxmox, ESXi home-lab & NAS storage
- Packing List: HBA Card ×1; 2× SFF-8643 to 4× SATA cables (8× SATA ends). --Cables in box are for SATA drives. They are not compatible with SAS drives. To connect SAS drives, use SFF-8643 to 8482 SAS cables (sold separately) or our matched HBA + cable kit.
How to isolate the faulty part
- Capture the evidence first. Save operating-system and controller logs, ZFS or RAID status, and timestamps before clearing errors or changing parts. Note whether the fault occurs at boot, during sustained load, only on writes, or during a scrub.
- Test the drive and bay separately. Move a suspect drive to a known-good bay, then try a known-good drive in the suspect bay. If the error follows the disk, the drive becomes a stronger suspect; if it stays with the bay, a path issue is more likely. These tests alone do not distinguish an HBA fault from a cable, expander, or backplane fault.
- Verify the physical path. Check power and cable seating, confirm connector types, and trace the actual front- and rear-backplane wiring for the specific chassis. Change one variable at a time so you can tell which change affected the result.
- Compare the controller and cable path. Where practical, test the suspect HBA with a known-good cable and path, or substitute a known-good compatible HBA while keeping the other components constant. If the failure follows the controller, the HBA becomes a stronger suspect. If it remains with a bay or backplane path, investigate the cable, expander, backplane, and power path.
- Reproduce load-related symptoms with logs running. If errors coincide with heavy I/O, record HBA temperature and controller reset messages during a repeatable workload. The community discussion does not establish a validated overheating threshold, so do not treat a suggested temperature as a manufacturer limit.
Check the chassis wiring before interpreting which drives should appear
SC847 configurations can differ in backplanes, connectors, and cable routes. Supermicro’s SC847 JBOD manual describes HBA cabling and head-unit/JBOD connectivity combinations. Verify the exact chassis variant and trace the route between the HBA, expander, and relevant backplane; do not assume every SC847 has the same wiring layout.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Use the symptom pattern to guide the next test
| Observed pattern | What it helps distinguish | Next useful check |
|---|---|---|
| Error follows a drive to a known-good bay | Raises suspicion of the drive, though it does not prove the drive is at fault. | Check that drive’s logs and status; keep the original timestamps. |
| Known-good drive shows the symptom in one bay | Points toward that bay’s path, but does not identify whether the cable, expander, backplane, or power is responsible. | Trace the bay’s wiring and test the path’s components one at a time. |
| Errors follow the HBA after a controlled substitution | Makes the controller a stronger suspect. | Review controller logs and firmware details, and verify compatibility before choosing a replacement. |
| Errors appear across multiple paths or only under heavy I/O | May implicate a shared component or a load-sensitive fault; the pattern alone cannot identify one. | Record resets and temperatures while reproducing the workload, and check shared cabling, power, and topology. |
The pattern narrows the investigation; it does not uniquely identify a component. Avoid replacing a rear backplane solely because the affected drives sit at the rear. The controller, cabling, expander topology, drives, backplane, and power supply all contribute to the storage path.
Quick Recap
Best Value
Rank #4
- Designed for LSI 9207 & 9300-8i compatibility; built with SAS3008 controller. Operates in IT Mode to enable direct disk passthrough functionality.
- Firmware: IT Mode (Non-RAID). Supports transfer speeds up to 12Gb/s for SAS and 6Gb/s for SATA. Ideal for JBOD setups and software-managed storage.
- Equipped with PCIe 3.0 x8 interface and dual SFF-8643 internal ports. Supports up to 8 drives directly, with expansion capability via SAS expanders.
- Suitable for ZFS, TrueNAS, FreeNAS, unRAID, Proxmox, ESXi, and NAS environments. Ideal for home labs, server builds, and disk passthrough applications.
- Package includes 1 HBA card and 2 SFF-8643 to SFF-8482 SAS cables. Included cables support SAS drives only. SATA drives require separate SFF-8643 to SATA breakout cables.
Rank #3
- Compatible with: LSI 9300-8i; Controller: LSI/Broadcom SAS3008 12Gb/s SAS HBA controller for server, NAS, workstation and home-lab storage builds.
- Firmware (FW): HBA IT Mode (Non-RAID); Data Transfer Rate: up to 12Gbps SAS and SATA 6Gbps, designed for direct disk passthrough and software-defined storage.
- Host Interface: PCIe 3.0 x8; Internal Connectors: 2× Mini-SAS HD SFF-8643. Direct attach up to 8 drives, and expand via external SAS Expander for large arrays.
- PERFECT FOR: ZFS, FreeNAS/TrueNAS, unRAID, Proxmox, ESXi home-lab and NAS storage builds that need stable HBA passthrough for SAS or SATA drives.
- Packing List: HBA Card: 1; SFF-8643 to 4× SFF-8482 SAS Cables: 2. Cables in box are for SAS drives. They are not compatible with SATA drives. To connect SATA drives, use SFF-8643 to 4× SATA cables sold separately or our matched HBA + cable kit.
Rank #2
- Compatible with: LSI 9300-8i & 9211-8i; Controller: Broadcom/LSI SAS3008 (12Gb/s SAS3, 8-port)
- Firmware (FW): HBA IT Mode (Non-RAID); Data Transfer Rate: up to 12Gbps SAS, SATA 6Gbps
- Host Interface: PCIe 3.0 x8; Internal Connectors: 2× Mini-SAS HD SFF-8643. --Direct attach up to 8 drives, and expand via external SAS Expander for large arrays
- PERFECT FOR: ZFS, FreeNAS/TrueNAS, unRAID, Proxmox, ESXi home-lab & NAS storage
- Packing List: HBA Card: 1; SFF-8643 to 4× SATA Cables: 2. Cables in box are for SATA drives. --They are not compatible with SAS drives. To connect SAS drives, use SFF-8643 to SFF-8482 cables (sold separately) or our matched HBA + cable kit
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