RAID Failure and Missing Disks

RAID Failed or Failed Rebuild (RAID 4/5/10)

When a RAID array experiences a “FAILED” or “FAILED REBUILD” status, it indicates a critical issue within the array. Let’s break down the terms:

RAID FAILED

A “RAID FAILED” status typically means that one or more drives within the RAID array have malfunctioned or failed. This failure can result from various issues, such as a physical disk failure, data corruption, or a connection problem.

FAILED REBUILD

A “FAILED REBUILD” status occurs when the RAID system attempts to reconstruct or rebuild data on a new drive to replace a failed one, but the process encounters errors or is unsuccessful. If this process fails, it may leave the array in a vulnerable state.

Common Causes:

Drive Failure: The most common cause is the failure of one or more physical hard drives in the RAID array.
Data Corruption: If data on the failed drive is corrupted, it may hinder the rebuilding process.
Multiple Drive Failures: If multiple drives fail simultaneously or during the rebuilding process, it can lead to a FAILED REBUILD.

Implications:

Data Loss: A RAID FAILED or FAILED REBUILD situation poses a risk of data loss, especially if redundancy measures are compromised.
Array Vulnerability: The array becomes vulnerable during the time it is in a failed state because it lacks the redundancy or parity required for fault tolerance.

If a RAID volume is missing a disk, it means the disk failed, or that the data on it was damaged in some way, and it is not connecting to your RAID volume.

BACKUP immediately.

(If your volume is not mounting, there may be a separate issue where the directory is damaged. A data recovery app such as Disk Drill or R-Studio may be required to recover the data from this volume.)

Troubleshooting

1. Determine if the disk is present

Launch SoftRAID, and click on the RAID volume.

Does the Application show the volume has having all disks present?

If yes, the problem may have corrected itself, you need to open the SoftRAID log for more information.

If the volume shows “missing disk”, then you need to determine whether the disk is present or not.

Look at the list of drives in the disks column, are they all present? Is there a disk present, that is not showing as “linked” to the volume?

If the disk is NOT present, skip to step 4 below.

2a. The disk is present, but it links to another volume of the same name and shows “missing disks”. Contact OWC Technical support. This problem may require special handling by OWC support.

2b. The disk is present, but has no links to any volume, but it has a SoftRAID icon on the disk tile. Unmount your volume. Wait 2 minutes. Remove the disk. Use SoftRAID to Mount the volume. If the volume mounts normally, then you can insert the disk, and “initialize it. Then go to step 3 below.

2c. The Disk is present but has a ? on the drive tile. This disk may have failed. Look at the disk tile for this drive.

• Does it show any additional information, such as capacity? Serial Number? SMART information?

These are clues whether the drive is failed, or simply has had data overwritten onto a “prohibted” part of the disk partition map area, so SoftRAID cannot read the drive. If the drive looks normal, then:

This disk has its partition map damaged, such that SoftRAID cannot read it. You will need to initialize the disk and add it back to the volume.

Unmount your volume. Wait 2 minutes. Remove the disk. Use SoftRAID to Mount the volume. If the volume mounts normally, then you can insert the disk, and “initialize it. Then go to step 3 below.

If the drive tile is mostly empty, then the disk may have failed. We recommend you certify the disk and see if it passes or fails. If it fails the certity, replace the disk. If it passed, then you can initialize the disk. Make sure it looks normal in the disk tile, identical to your other drives for your volume. Then go to step 3 below.

3. Add the disk back to the volume

Select the volume tile for the volume. In the volumes menu, “Add Disk”. Check the volume “optimization” and change it to Workstation, or Server if necessary. Server will rebuild the volume at 100% speed, but this may cause your volume to be slow. Workstation is a balance between rebuilding speed and user performance, a rebuild will proceed at 50% of its potential speed, then 100% when you are not using the computer. All other optimization settings will pause the rebuild, until you stop using the computer for a while.

4. The Disk is missing from the disks column

Launch SoftRAID.

Use the Blink Disk Light Feature to notate where each of the remaining disks are in your enclosure (this cannot be easily done with NVMe drives, contact OWC Support if an NVMe drive is missing). Once you identify the disk that is not present, remove it from the enclosure, and carefully reinsert it. Make sure it is firmly seated. Listen for it to spin up.

Does it show up in the disks column now?

If it does, then go to section 1 or 2 above. If it does not, or shows up with a SMART failure, replace the disk.

A RAID 0 volume that is missing a disk cannot mount. If a disk has failed, you have lost all data on this volume.

If the disk is showing up in the disk column, but is not linked to the volume, it is possible OWC support specialists can recover your data, if you are not fully backed up. Do not rely on this, always be sure to backup RAID 0 volumes frequently. Contact OWC support.

If the disk is not showing in the disks column: Use the Blink Disk Light Feature to notate where each of the remaining disks are in your enclosure (this cannot be easily done with NVMe drives, contact OWC Support if an NVMe drive is missing)

Once you identify the disk that is not present, remove it from the enclosure, and carefully reinsert it. Make sure it is firmly seated. Listen for it to spin up.

Does it show up in the disks column now?

If not, you need to replace the disk.
If it does, and your volume mounts, then you should back up your data. It’s possible there was a bad connection from your drive to the enclosure. (This should only be the case on an enclosure that is several years old, or is in a high humidity environment. Consider getting a new enclosure.