A file management method, a distributed storage system, and a management node are disclosed. In the distributed storage system, after receiving a file creation request sent by a host for requesting to create a file in a distributed storage system, a management node allocates, to the file, first virtual space from global virtual address space of the distributed storage system, where local virtual address space of each storage node in the distributed storage system is corresponding to a part of the global virtual address space. Then, the management node records metadata of the file, where the metadata of the file includes information about the first virtual space, and the information about the first virtual space is used to point to local virtual address space of a storage node that is used to store the file. Further, the management node sends, the information about the first virtual space to the host.