The maintenance personnel found that the storage fault indicator was on. After logging into the management interface, they found that there was a RAID group degradation alarm and directly located…

The maintenance personnel found that the storage fault indicator was on. After logging into the management interface, they found that there was a RAID group degradation alarm and directly located that a hard disk was faulty. By replacing the hard disk, the fault was eliminated. During this process, the maintenance personnel used which of the following basic troubleshooting methods?