Almost all of these problems are system call errors that occur when TiKV writes data to the disk, for example, Io(Os {code: 13, kind: PermissionDenied...}) or Io(Os {code: 2, kind: NotFound...}).
To address such problems, first check the mounting method and the file system of the backup directory, and try to back up data to another folder or another hard disk.
For example, you might encounter the Code: 22(invalid argument) error when backing up data to the network disk built by samba.