There are several reasons why a ZFS scrub may not complete:
Failing hardware: If any hardware components of the system, such as disks or memory modules, are faulty, it can cause the scrub to fail or halt. You can check the system logs or run hardware diagnostics to identify any hardware issues.
Power failure: If there is a power failure during the scrub, it can cause it to stop and not complete. Ensure that your system is connected to an uninterrupted power supply (UPS) to prevent such issues.
Errors encountered during the scrub: If the scrub encounters any errors, such as bad sectors on a disk or corrupt data, it may halt and not complete. You can check the system logs to identify any error messages and take corrective actions accordingly.
Issues with partition matching: If there are any issues with partition matching, the scrub may not complete. Ensure that all the partitions are properly matched and configured before running the scrub.
By identifying and addressing these issues, you can improve the chances of the ZFS scrub completing successfully.