A Linux engineer is troubleshooting a newly added SCSI device for a Linux server that needed more disk space without rebooting. The engineer discovers that the new device is not visible by the Linux…

Question

Options

• Aecho "- - -" > /sys/class/scsi_host/host0/scan
• Becho ' ' > /sys/class/scsi_host/host0/scan
• Cecho "- - -" > /sys/scsi/scsi_host/host0/scan
• Decho "scan" > /sys/class/scsi_host/host0/scan

• A
  71% (36)
• B
  8% (4)
• C
  18% (9)
• D
  4% (2)

Explanation

The correct command is 'echo "- - -" > /sys/class/scsi_host/host0/scan'. The three dashes represent wildcard values for channel, target ID, and LUN respectively, instructing the SCSI subsystem to scan all possible combinations on host0 - effectively a full bus rescan. The correct sysfs path is /sys/class/scsi_host/ (not /sys/scsi/scsi_host/ as in option C, which is an invalid path). Option B uses a space character instead of '- - -', which is not the correct syntax and will not trigger a valid rescan. Option D echoes the word 'scan' which is also invalid - the kernel expects the '- - -' wildcard format. This is a standard Linux procedure for making hot-added SCSI/SAS/iSCSI devices visible without a reboot.

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