The GFS Shared File System explained in this guide does not provide the following functions:
Use as a root file system, /usr, /var, /opt
To use as a mount point
quota function
ACL function
Asynchronous I/O function
File sharing with other nodes by an NFS
Setting of hard link for a directory
Direct I/O function
Mandatory file lock
File creation and access of the following file types:
Block special files
Character special files
Named pipes
Sockets
The strict file terminal management in the case of write(2) for open(2) file for which specified O_APPEND compete with write(2) from other nodes
Guaranteeing the atomicity of the write for the following operations from other nodes, when data written by write(2), writev(2), pwrite(2) is stored in several blocks.
write(2), writev(2), pwrite(2), truncate(2), ftruncate(2), creat(2), open(2) (with O_TRUNC)
Changing PROT_READ and PROT_WRITE using mprotect(2)
Enabling lease between nodes using fcntl(2) with F_SETLEASE or F_GETLEASE.
Using remap_file_pages(2) or mmap(2) with MAP_POPULATE
mmap(2) from another node to a writable file opened by open(2)
Writable open(2) from another node to a file mapped by mmap(2)
open(2) from another node to a mmap(2) file for which MAP_SHARED and PROT_WRITE are specified
mmap(2) which specifies MAP_SHARED and PROT_WRITE from another node to a open(2) file
Assurance of data consistency when mmap(2) is executed for open(2) files from other nodes
Assurance of data consistency when open(2) is executed for mmap(2) files from other nodes
Using fallocate(2)
Mounting function using mount(8)
Unmounting function using umount(8)
Using open(2) with O_TMPFILE to generate an unnamed temporary file
Sharing physical data blocks between multiple files (reflink)
Using renameat2(2) with flags other than RENAME_NOREPLACE
Suspending and resuming new modifications to the filesystem using fsfreeze(8)
