"Device is busy" is a common error message that you may encounter when trying to unmount a device on a Linux system. This error occurs when the system detects that a file or process is still actively using the device
and therefore it cannot be unmounted at that time.
In this article
I will explain why this error occurs
how to identify the process that is using the device
and different ways to resolve the issue.
1. Why does the "Device is busy" error occur?
When you attempt to unmount a device
the operating system first checks if any files or processes are currently using the device. If it finds any active connections or open files
it considers the device to be busy and prevents unmounting to avoid data loss or corruption.
2. Identifying the process using the device
To identify the process that is causing the "Device is busy" error
you can use the `lsof` command. 'lsof' stands for “list open files” and it provides information about files and processes currently running on the system.
To use the `lsof` command
open a terminal and type the following command:
```shell
$ lsof | grep /mount/point
```
Replace '/mount/point' with the actual mount point of the device you are trying to unmount. This command will display all the processes that have an active file handle on that device.
3. Resolving the "Device is busy" error
a) Closing open files: If the device is busy because of open files
consider closing them. Identify which files are open using the `lsof` command as described above. Once you have identified the files
close them by using the appropriate application or command. Once all files are closed
you should be able to unmount the device without any issues.
b) Killing processes: In some cases
a process might be actively using the files on the device
and closing the files is not sufficient. In such cases
you can kill the processes that are using the device.
To kill a process
you need to know its process ID (PID) which you can find using the `lsof` command. Once you have the PID
use the `kill` command with the PID to terminate the process. For example:
```shell
$ kill PID
```
Replace 'PID' with the actual PID of the process you want to kill. Once the process is terminated
you should be able to unmount the device.
c) Unmount forcibly: If the above methods do not work or are not feasible
you can forcefully unmount the device. This method should be used with caution as it can potentially cause data loss or corruption. To forcibly unmount a device
use the following command:
```shell
$ umount -f /mount/point
```
Replace '/mount/point' with the actual mount point of the device. Note that forcibly unmounting may result in the loss of unsaved data or cause system instability.
4. Conclusion
The "Device is busy" error occurs when the system detects that a file or process is actively using the device. To resolve this issue
you can close open files
kill processes using the device
or forcibly unmount the device. It is important to be cautious while forcibly unmounting to avoid data loss or system instability. By following the steps outlined in this article
you should be able to successfully resolve the "Device is busy" error and unmount the device.