Considerations for GPFS applications

Application design must consider the exceptions to the Open Group technical standards for the stat() system call and NFS V4 ACLs. Also, a technique to check if a file system is controlled by GPFS™ has been provided.

Consider the following:

Exceptions to Open Group technical standards
GPFS is designed in a way that most applications written to the Open Group technical standard for file system calls can access the GPFS data without any modification. However, there are some exceptions.
Determining if a file system is controlled by GPFS
A file system is controlled by GPFS if the f_type field in the statfs structure returned from a statfs() or fstatfs() call has the value 0x47504653, which is GPFS in ASCII.
GPFS exceptions and limitations to NFS V4 ACLs
GPFS has some exceptions and limitations for the NFS V4 ACLs.
General NFS V4 Linux exceptions and limitations
GPFS has some NFS V4 Linux exceptions and limitations.
Considerations for the use of direct I/O (O_DIRECT)
A file opened in the O_DIRECT mode ("direct I/O"), GPFS transfers data directly between the user buffer and the file on the disk.
NFS protocol node limitations
NFS protocol nodes have conflicting NLM locking services between the Linux kernel and CES NFS.

Parent topic: Administering