Supporting coordinated access to a file system's shared storage using automatic alignment of a parallel file access protocol and metadata management

A file system of supporting coordinated access to the file system's shared disk storage subsystem using an automatic alignment of a parallel file access protocol and metadata management on a per object basis of said storage subsystem, said file system comprising:

• a shared disk storage subsystem that stores said file system's shared data;
• a plurality of file servers in a cluster, each of the file servers that are active having equivalent access to the shared data, wherein a particular file server (among said servers) is configured to manage metadata for a particular file;
• and
• wherein a file server, among said servers, receives a client's request to access a file stored by said file system in said storage subsystem using a parallel file access protocol:
• if said file system has selected a file server to serve as a metadata manager of said file, using the selected file server to coordinate access to said file's metadata,
• if said file system has not selected a file server to serve as the metadata manager of said file, selecting the file server that received said request as the metadata manager for said file until a file close request operation is received, and
• said server that received the client's request:
• (i) performing a file open request operation for said file, to the file server selected to serve as the metadata manager, (ii) opens said file and creates a file handle of said file, (iii) encodes a file server ID, of the file server selected as the metadata manager of said file, in the file handle such that said file system's file servers may identify which file server is said file's metadata manager, and (iv) returns the file handle to said client for performing I/O to said file;
• wherein if the file server that received said client's request is not the metadata manager and a metadata manager already exists for the file but no clients have said file open, the file system migrates the metadata management from the file server, previously selected as the metadata manager of said file, to a file server in the cluster that at least one client has said file open.

A computer program product of supporting coordinated access to a file system's shared disk storage subsystem using an automatic alignment of a parallel file access protocol and metadata management on a per object basis of said storage subsystem, wherein active file servers in a cluster have equivalent access to shared data of said file system, said program product comprising a non-transitory computer readable storage medium having computer usable program code embodied therewith, said program code being readable/executable by a file system to:

• in response to a client's request to access a file stored by said file system in said storage system using a parallel file access protocol:
• if said file system has selected a metadata manager of said file, use said metadata manager to coordinate access to said file's metadata;
• if said file system has not selected a metadata manager of said file, select the file server that received said request as the metadata manager for said file until a file close request operation is received;
• perform a file open request operation for said file to the selected metadata manager, said performing being done by a file server that received said request;
• open said file and create a file handle of said file;
• encode a file server ID, of the file server selected as the metadata manager of said file, in the file handle such that said file system's file servers may identify which file server is said file's metadata manager;
• and
• return the file handle to said client for performing I/O to said file.
• if a file system file server that received said client's request is not the metadata manager and a metadata manager already exists for the file but no clients have said file open, migrate the metadata management from the file server, previously selected as the metadata manager of said file, to a file server in the cluster that at least one client has said file open.