To identify the root cause:

1. Run the following command to check the status of Mogile File System and see if there is a "REQUEST FAILURE" on any storage device:

   # Check the status of Mogile File System
   sudo mogadm check
   # dev11 encountered "REQUEST FAILURE" error.

   Example:

   

2. Double-check if the device has been unmounted in File System:

   # Check the status of Mogile File System
   sudo df -h
   # dev11 isn't be listed.

   Example:

   

To fix the issue:

Case 1

The storage device has been added into /etc/fstab as a entry:

1. Check /etc/fstab:

   cat /etc/fstab

   

2. Mount the device again:

   sudo mount /storage/mogdata/dev11

Case 2

The storage device has been added into /etc/rc.local as a mount point, especially for remote storage devices:

1. Check /etc/rc.local:

   cat /etc/rc.local

   Example:

   

2. Mount the device again:

   cat /etc/rc.local

To verify:

1. Check the status of Mogile File System again:

   # Check the status of Mogile File System
   sudo mogadm check

   Example:

   

2. Go to the Dashboard and check the System Status: