Edge server and storage control method

An edge server configured to perform overwrite preventive processing of a corresponding file in a core server, comprising:

• a communication interface device which is configured to communicate with a core server;
• and
• a processor which is connected to a memory and the communication interface device and configured to provide a first home directory and write a file in the first home directory according to a write request to the first home directory, wherein
• the core server provides a core space,
• the core space is a file system space to become a copy destination of updates of files and directories of each of the first home directory and a second home directory,
• the first home directory is a first file system space used by a user,
• the second home directory is a second file system space used by the user and provided by a separate edge server,
• wherein a first file is a file in the first home directory that has been updated,
• the preventive processing is executed by the processor and includes the processes of:
• creating a first directory in the first home directory;
• copying the first file to the first directory while maintaining a path structure of the first file;
• copying the first directory to the core space as the process of copying the update of the first home directory to the core server;
• creating a second directory in the first home directory;and
• moving directories, excluding the second directory, and files belonging to a route directory of the first home directory to the second directory while maintaining the path structure,
• wherein the first file copied to the first directory is a same file as a file in the files that have been moved to the second directory, and the path structure of the first file in the second directory is a same as the path structure in the first directory,
• wherein the second file is a file that has been updated in the second home directory and copied to the core space, and
• wherein the first file is a file that corresponds to the second file and has not been copied to the core space.