RAID Members Inactive: Diagnostics & Troubleshooting

When drives are missing from a RAID

An inactive RAID member refers to a component of a redundant array of independent disks (RAID) that is not actively participating in the array's operations. This can happen due to various reasons, such as a disk failure, disconnection, or other issues. Diagnosing and solving inactive RAID members typically involve using specific tools and following a set of steps.

Here's a overview approach to tackle this problem:

Check RAID status

Use the following command to check the status of your RAID array:

cat /proc/mdstat

This command will provide information about the current state of your RAID array, including any inactive members.

Identify inactive members

Look for any RAID devices that are marked as inactive in the output of the previous command. It will typically be indicated by "(I)" or "inactive" next to the device name.

Physical inspection

If the RAID member is a physical disk, physically inspect it to ensure it is properly connected. Check for loose cables or any signs of hardware failure.

Disk health check

Run disk health diagnostics tools, such as smartctl, to examine the health and integrity of the inactive disk. For example:

smartctl -a /dev/sdX

Replace "/dev/sdX" with the appropriate device identifier for your disk.

Check log files

Review system log files (e.g., /var/log/messages or /var/log/syslog) for any error messages related to the inactive RAID member. These logs may provide additional insights into the cause of the issue.

Rebuild or re-add the inactive member

Depending on the cause of the inactivity, you can take different steps to resolve the issue. Here are a few common scenarios:

Disk failure: If the inactive member is due to a failed disk, you will need to replace the faulty disk with a new one. Follow your RAID controller or software's instructions for replacing failed disks and rebuilding the array.
Disconnected disk: If the inactive member is caused by a disk that became disconnected, you can attempt to reconnect it and see if it becomes active again. Ensure all cables are securely connected and power on the disk if necessary.
Configuration or software issue: In some cases, an inactive member might be caused by a configuration error or a software issue. Check the configuration files for your RAID software (e.g., mdadm) and ensure that the member is correctly defined in the array's configuration. You may need to re-add the member to the array manually using commands like:
```
mdadm --manage /dev/mdX --add /dev/sdX
```
Replace /dev/mdXwith the appropriate RAID device and /dev/sdX with the inactive member.
Monitor the rebuilding process: After taking the necessary steps to resolve the issue, monitor the RAID rebuilding process. You can use tools like mdadm or RAID management software specific to your system to check the progress.

It's important to note that the specific steps and tools may vary depending on the RAID implementation and Linux distribution you are using. Consult your system's documentation or the RAID software's documentation for more detailed and accurate instructions based on your setup.