GPFS: Administration and Programming Reference - IRA Home

mmchfs Command
Name
mmchfs – Changes the attributes of a GPFS file system.
Synopsis
mmchfs Device [-A {yes | no | automount}] [-E {yes | no}] [-D {nfs4 | posix}] [-F MaxNumInodes] [-k
{posix | nfs4 | all}] [-m DefaultMetadataReplicas] [-o MountOptions] [-Q {yes | no}] [-r
DefaultDataReplicas] [-S {yes | no} ] [-T Mountpoint] [-V] [-z {yes | no}]
Or,
mmchfs Device [-W NewDeviceName]
Description
Use the mmchfs command to change the attributes of a GPFS file system.
All files created after issuing the mmchfs command take on the new attributes. Existing files are not
affected. Use the mmchattr command to change the replication factor of existing files.
Parameters
Device
Options
The device name of the file system to be changed.
File system names need not be fully-qualified. fs0 is as acceptable as /dev/fs0. However, file
system names must be unique across GPFS clusters.
This must be the first parameter.
-A {yes | no | automount}
Indicates when the file system is to be mounted:
yes When the GPFS daemon starts.
no Manual mount.
automount When the file system is first accessed.
-D {nfs4 | posix}
Specifies whether a ’deny-write open lock’ will block writes, which is expected and required by
NFS V4. File systems supporting NFS V4 must have -D nfs4 set. The option -D posix allows NFS
writes even in the presence of a deny-write open lock. If you intend to export the file system using
NFS V4 or Samba, you must use -D nfs4. For NFS V3 (or if the file system is not NFS exported
at all) use -D posix.
-E {yes | no}
Specifies whether to report exact mtime values. If -E no is specified, the mtime value is
periodically updated. If you desire to always display exact modification times, specify the -E yes
option.
-F MaxNumInodes
Changes the maximum number of files that can be created. Allowable values range from the
current number of created inodes (determined by issuing the mmdf command), through the
maximum number of files possibly supported as constrained by the formula:
maximum number of files = (total file system space/2) / (inode size + subblock size)
Chapter 8. GPFS commands 103