Which file should be checked for problems with RAID?

The file that should be checked for problems with RAID is /proc/mdstat. This file provides real-time information regarding the current status of RAID devices on a Linux system that utilizes the MD (multiple devices) driver. It details the state of the RAID arrays, including information such as their configuration, active drives, and any error states that may be present. If there are issues with the RAID setup—such as degradation or failed disks—this file will indicate the status of each RAID array, making it an essential resource for troubleshooting.

Other files mentioned have different functions: /var/log/syslog records system-wide logs, which may include some RAID-related messages but is not specifically focused on RAID status. /etc/raid.tab is not typically used on most modern Linux systems, as it was associated with older RAID management tools. /proc/partitions provides information about the system's partitions but lacks the specific RAID status details that /proc/mdstat offers. Therefore, checking /proc/mdstat is the most direct and effective method for diagnosing RAID-related issues.