Linux – Unclaimed disk space but no actual physical disk present

hard drivelinuxstorage

I am working with Ubuntu server 12.04 and earlier this week we detected a bad disk in /dev/sdl. I was not able to query its mount point and it also had failed SMART tests.

Today I brought a brand new hard disk to replace the failed one (same brand and model)

However after installing the drive, I run:

  $ dmesg -t | tail

to see if the drive has been detected. Unfortunately I am not able to detect the drive.

Here is the output of lshw | grep -A 5 disk.

  disk:10 UNCLAIMED
  description: SCSI Disk
  physical id: 0.a.0
  bus info: scsi@6:0.10.0

How can this appear regardless of whether I have a disk in there or not?

My process for replacing failed disks is this:

  • Physically locate bad disk
  • Unmount and remove bad disk
  • Insert new disk, run dmesg | tail to show disk is present
  • Format disk
  • Mount disk

For all the other disks, dmesg showed when they were inserted but not this time. Any thoughts?

Best Answer

Due to the age of this question, it may be safe to assume the system's been rebooted. However, there's another way to trigger a re-scan of the either the entire SCSI bus or just the device itself.

  • Re-Scan the entire SCSI bus

    echo "- - -" > /sys/class/scsi_host/host0/scan

  • Re-Scan just the device itself

    echo 1 > /sys/class/scsi_device/0:0:0:0/rescan

Note: You will have to confirm if host0 or 0:0:0:0 are correct for that host/drive.

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