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Storage Disks — Troubleshooting

Cannot Attach Disk — Attach Option Is Grayed Out​

Symptom: The action menu (⋮) shows Attach but the option is disabled or does not appear.

Cause: The disk is in In-use status — it is already attached to another Instance.

Resolution:

  1. Check the Attached Instance column to see which Instance the disk is currently attached to.
  2. Perform a Detach from that Instance first.
  3. Once the status returns to Available, attach the disk to the desired Instance.

Disk Was Detached But the Operating System Still Shows the Device​

Symptom: After detaching from the portal, lsblk or fdisk -l on the Instance still shows the old device.

Cause: You did not unmount the partition before detaching, or the kernel has not yet updated the device state.

Resolution:

  1. Run sudo umount /dev/<device_name> inside the Instance before detaching next time.
  2. If the device persists after detach, restart the Instance so the kernel refreshes the device list.

Important: Do not write data to the "phantom" device that remains — the data will not be saved because the disk has already been detached from the Instance.

Disk Is in Error Status and No Operations Can Be Performed​

Symptom: The Status column shows Error; all actions (Attach, Resize, Delete) fail.

Cause: An internal error occurred during disk creation or resize, or the storage node experienced a problem.

Resolution:

  1. Wait 5–10 minutes and refresh the page — the status sometimes recovers automatically.
  2. If the Error status persists after 15 minutes, contact FPT Cloud support with the Disk Name and Project ID.

Cannot Delete the Disk​

Symptom: The Delete option is disabled or the operation returns an error.

Common causes:

  • The disk is in In-use status (currently attached to an Instance).
  • The disk is in Creating or Resizing status (operation in progress).

Resolution:

  1. If In-use: perform a Detach first, then delete.
  2. If Creating / Resizing: wait for the operation to complete, then try again.

Newly Attached Disk Does Not Appear Inside the Instance​

Symptom: The disk was attached successfully (the portal shows In-use) but the new device is not visible inside the Instance.

Cause: The operating system has not yet recognized the new device, or the disk has not been partitioned and formatted.

Resolution:

  1. Inside the Instance, run sudo lsblk to list devices and sudo fdisk -l to see size details. Confirm the device name (for example /dev/vdb) by matching the size against the disk you created in the portal.

  2. Check whether the device already has a filesystem: sudo blkid /dev/vdb. If the command returns filesystem information (for example TYPE="ext4"), the device is already formatted — skip step 3.

  3. If the device has no filesystem, format it:

    Warning: This command permanently erases all data on the device and cannot be undone. Make sure you have identified the correct device name in step 1 before proceeding.

    sudo mkfs.ext4 /dev/vdb

  4. If the device does not appear at all after running lsblk, try detaching and reattaching from the portal.