Write to File System Fails


Before proceeding with troubleshooting, be sure to implement the following prerequisites for connecting to file systems from Linux-style instances:

Symptom 1: Writing to a file system from a mounted instance fails.

For example, open a terminal window on the instance and use the touch command to write a 'helloworld' file:

touch /mnt/yourmountpoint/helloworld

The write operation fails with the error:

touch: cannot touch '/mnt/yourmountpoint/helloworld': Permission denied

Cause: When a file system is created, the root user owns the root directory. If you're connecting from an instance that uses a Linux or CentOS platform image, the default user is opc. The default user is ubuntu when you connect from an instance that uses an Ubuntu platform image. These default users are not root users, so you can't initially write a file or directory to a new file system with these users.

Solution: You can implement one of the following solutions:

  • Connect as the root user. Then, create files or directories in the new file system.
  • Connect as the root user. Then, change the ownership or permissions of the file system root directory to allow other users (such as opc or ubuntu) to write to the file system.

  • Connect as the root user. Then, create subdirectories with ownership or permissions that allow other users to write to the subdirectory.

    Learn more about updating file and directory ownership and permissions.

  • Connect as the default user. Then, use the sudo command to write or to change permissions or ownership of files or directories. The sudo command temporarily provides a regular user with root user permissions. Here's an example of using the sudo command to write to the file system:

    sudo touch /mnt/yourmountpoint/helloworld

    Learn more about the sudo command.

    For more information about accessing instances, see Connecting to an Instance.