How are NVMe drives different from HDDs when diagnosing problems?

NVMe drives behave differently from HDDs in several important ways that affect how you diagnose problems:

• No moving parts — NVMe drives cannot be heard spinning up or down. You cannot listen for a drive to spin up after reseating it.
• Blink Disk Light does not work — The “Blink Disk Light” feature (Disk menu → Blink Disk Light) is only available for HDDs. It cannot be used to identify which physical slot an NVMe drive occupies.
• Thermal sensitivity — NVMe drives can throttle or hang when they overheat, especially during intensive operations like certification or heavy sustained reads/writes.
• TRIM behavior — NVMe drives use TRIM for wear leveling, which can affect parity accuracy in RAID 4/5 volumes (see critical section below).
• Flash wear — Unlike HDDs, NVMe drives have a finite write lifespan tracked by a media wear indicator. When media wear reaches 0%, the drive should be replaced immediately.

How do I identify which physical slot an NVMe drive is in?

Because Blink Disk Light is not available for NVMe drives, identifying the physical location of a specific NVMe drive requires a different approach.

Using the SoftRAID disk tile: Each disk tile in SoftRAID shows the drive’s serial number. You can cross-reference the serial number with the label on the physical drive to determine its location.

Using the SoftRAID log: When a drive disappears or causes an error, the SoftRAID log (Utilities menu → SoftRAID Log) records the drive’s SoftRAID ID. You can match this to the disk tile by selecting each tile and noting its ID.

Assign unique labels: Before a problem occurs, label each NVMe drive in SoftRAID (select the disk tile, then edit the label field). The log will reference the label by name, making it easy to identify the problem drive.

If you still cannot identify the drive: Contact OWC Support at https://software.owc.com/support/supportform/ — support specialists have additional tools to help identify which physical drive corresponds to the missing or failing disk.

An NVMe drive is missing from the SoftRAID disk list. What do I do?

For NVMe drives, Blink Disk Light cannot be used. Follow these steps:

• Check the SoftRAID log (Utilities menu → SoftRAID Log) — look for the SoftRAID ID of the missing drive.
• Identify which drive is missing by comparing drive serial numbers in SoftRAID’s disk tiles against the drives in your enclosure.
• Reseat the drive — power down the enclosure if it does not support hot-swap for NVMe. Remove the drive, inspect the connector for damage, and firmly reinsert it.
• Restart SoftRAID and check if the drive reappears.
• If the drive reappears — certify it (Disk menu → Certify Disk) to confirm it is still reliable, then add it back to the volume (Volume menu → Add Disk).
• If the drive does not reappear — the drive has likely failed. Contact OWC Support immediately.

Important: NVMe drives that go missing and reappear are not necessarily in a safe or known state. Always certify a reappearing NVMe drive before trusting it.

An NVMe drive is ejecting and reappearing. What does this mean?

Unlike HDDs (which may eject due to enclosure slot issues or cable problems), flash media that ejects and then reappears is almost always an early sign of drive failure or overheating.

• NVMe drives do not reset and reappear immediately after a genuine hang — if a flash drive ejects and quickly reappears, the drive itself is likely failing.
• Check SMART status — if the drive shows predicted failure, media wear below 10%, or SMART test failure, replace it immediately.
• Check for overheating — if the eject occurred during intensive sustained use (certification, large transfers), thermal throttling may be a factor. See the section below on overheating.
• Action: If a flash drive in a stable enclosure ejects and reappears, plan to replace the drive.

My NVMe drive seems to be running slowly or stalling during certification or heavy use. Is it overheating?

NVMe drives are sensitive to heat, especially in enclosed or poorly ventilated environments. Sustained read/write operations (such as certification or large file copies) can cause an NVMe drive to thermally throttle — reducing its speed — or in extreme cases, temporarily hang.

Signs of thermal throttling:

• Certification speed that starts fast then drops significantly
• Disk Hung errors during intensive operations
• Intermittent I/O errors during certification that clear up after the drive cools

What to do:

• Ensure your enclosure has adequate airflow. Avoid placing enclosures in enclosed spaces like drawers or cabinets.
• Check that enclosure fans are spinning and the unit is not abnormally hot to the touch.
• If you suspect overheating, pause the operation, allow the drive to cool for 15–30 minutes, and resume.
• Do not certify NVMe drives in sealed or fanless enclosures without confirming the thermal design supports sustained write workloads.

Note: SoftRAID’s certification process writes intensively to every sector — it is one of the most thermally demanding workloads an NVMe drive can experience. This is normal and by design; it is the most reliable way to detect marginal drives.

How long does it take to certify an NVMe drive?

Certification time for NVMe drives depends heavily on whether the drive has direct PCIe bandwidth or shares Thunderbolt bandwidth with other drives.

NVMe on Accelsior PCIe card (direct PCIe, full bandwidth per drive):

• 2TB NVMe: ~2–4 hours
• 4TB NVMe: ~4–8 hours
• Maximum throughput: up to 7,000 MB/s per drive (PCIe 4.0 x4)

NVMe in Thunderblade enclosures (bandwidth shared across all drives via Thunderbolt 3, ~2,800 MB/s total):

Key point: More drives in a Thunderblade means longer per-drive certification times because all drives share the same Thunderbolt connection. A 12-drive Thunderblade will certify much slower per drive than a 4-drive Thunderblade even if the drives are identical.

My NVMe certification failed. What does that mean?

A properly functioning NVMe drive should always pass certification. Any failure confirms a hardware issue. Check the SoftRAID log (Utilities menu → SoftRAID Log) and look for the failed certification entry.

Cause 1: Communication problem 
If errors appear at sector offset 0 (“Type B” errors), or if multiple drives failed at the same timestamp, the issue is likely a connection or bus problem, not the drive itself.

• Check all Thunderbolt/PCIe connections
• Prevent your Mac from sleeping during certification (System Settings → Energy)
• Avoid other devices on the same Thunderbolt bus during certification
• Resume certification — SoftRAID will continue from where it stopped

Cause 2: Faulty NVMe drive 
If errors appear at a specific non-zero sector offset (“Type A” errors), or if the disk tile shows SMART failure or predicted failure, the drive is bad.

• Replace the drive immediately
• If the drive is new (DOA), contact OWC for a replacement under warranty

Cause 3: Thermal throttling during certification 
If errors are intermittent and the enclosure or drive is hot, allow the drive to cool and resume. See the overheating section above.

Important: Do not certify an NVMe drive whose media wear indicator is below 10%. The intensive write workload of certification may accelerate failure on a nearly worn-out drive. Replace it instead.

SMART monitoring for NVMe drives — what does SoftRAID check?

SoftRAID monitors NVMe drives for all standard SMART parameters plus flash-specific wear indicators. SoftRAID runs SMART checks once per day and every time you launch SoftRAID.

For NVMe drives specifically, SoftRAID monitors:

• SMART test status (pass/fail)
• Media wear indicator — how much write life remains
• Media worn out status — indicates drive is at end of life
• Reallocated sectors (if applicable)
• I/O errors

Media wear thresholds:

Note: Most NVMe drives support SMART reporting fully, including Apple internal SSDs (though not officially documented by Apple).

Critical: Protecting RAID 4/5 Volumes with NVMe Drives (SoftRAID 8.0 Fix)

This applies to all users running RAID 4 or RAID 5 volumes with NVMe or SSD drives.

SoftRAID 8.0 fixed a driver bug that could cause file corruption if an NVMe or SSD fails or is replaced in a RAID 4 or RAID 5 volume. Without the fix, incorrect parity data could be written during a disk failure event — meaning a second disk failure would result in data corruption instead of a successful rebuild.

Action required based on your macOS version:

macOS 15.0 and later: After upgrading to macOS 15, validate your RAID 4 or RAID 5 volumes once: Volume menu → Validate.

macOS 14.7.4 and earlier: Two steps are required:

• Disable TRIM: SoftRAID menu → Settings → Disk → uncheck TRIM
• Validate your RAID 4 or RAID 5 volumes: Volume menu → Validate

The validate step only needs to be done once after disabling TRIM.

To speed up validation: Set volume optimization to Workstation or Server (Volume menu → Optimize for) before or during validation.

Why might I see blocks updated during validation of an NVMe RAID mirror?

After a rebuild of a mirror volume containing NVMe or SSD drives, validation may show that some blocks were updated. This is normal.

NVMe and SSD drives use TRIM technology for wear leveling, which constantly moves data around on the flash memory. Some blocks may have shifted since the rebuild, causing minor differences that validation corrects. This behavior is unique to flash media and does not occur with HDDs.

If validation reports a large number of blocks updated (significantly more than a few percent of the volume), contact OWC Support to investigate further.

Can I use RAID 4 or RAID 5 with NVMe drives? Which is faster?

Yes. RAID 4 is the preferred RAID level for NVMe and SSD drives. RAID 4 reads can be up to 20% faster than RAID 5 on flash media because only data disks are read — the dedicated parity disk is not accessed during normal reads.

Recommendation: Use RAID 4 (not RAID 5) for NVMe-based RAID volumes, especially for large-file workflows like video editing.

Important: If your NVMe RAID 4 or RAID 5 volume was created before SoftRAID 8.0, see the critical section above to verify your parity data is correct.

Getting Help with NVMe Drive Issues

If you have completed the steps above and are still experiencing problems with an NVMe drive, contact OWC Support:

Submit a support ticket. 

Before submitting, generate a SoftRAID Tech Support Report: Utilities menu → Generate Report for Tech Support. Attach it to your ticket for faster resolution.

Include in your ticket:

• Which NVMe enclosure or PCIe card you are using (Thunderblade, Accelsior, etc.)
• The macOS version you are running
• The SoftRAID version (SoftRAID menu → About SoftRAID)
• The RAID level of the affected volume
• A description of the problem (missing drive, certification failure, I/O errors, eject behavior)
• The SoftRAID Tech Support Report