If you receive the error "JBD: Barrier-based sync failed on md0-8 - disabling barriers," it means that there was an issue with the journaling block device (JBD) on the device md0-8 and the barrier-based synchronization has failed.
Barrier-based synchronization is a mechanism that is used by the JBD to ensure that data is written to the journal in a consistent and reliable manner. If the barrier-based synchronization fails, it can lead to data corruption and other issues.
To fix this error, you will need to identify the cause of the failure and take appropriate action. Some possible causes of this error include:
Hardware issues: If the device md0-8 is a hardware RAID array, it may be experiencing hardware issues, such as a failed disk or controller. In this case, you will need to replace the faulty hardware and rebuild the RAID array.
File system issues: If the file system on md0-8 is damaged or corrupt, it may cause the JBD to fail. In this case, you may need to repair the file system using a tool like fsck.
Software issues: There may be a bug in the software or kernel that is causing the JBD to fail. In this case, you may need to upgrade to a newer version of the software or kernel to fix the issue.
It's always a good idea to carefully review the logs and perform troubleshooting to identify the cause of the error and take appropriate action to fix it. This will help ensure that your system is stable and reliable.