GPFS: Administration and Programming Reference - IRA Home

mmchfs Command
If your file system has additional disks added or the number of inodes was insufficiently sized at
file system creation, you may change the number of inodes and hence the maximum number of
files that can be created.
The initial setting of the number of inodes at file system creation is used as the minimum value.
The new value, set by using the mmchfs command, determines the maximum value. The inode
file expands on demand, from the initial minimum value set up to the new maximum value as
needed.
For file systems that will be doing parallel file creates, if the total number of free inodes is not
greater than 5% of the total number of inodes, there is the potential for slowdown in file system
access. Take this into consideration when changing your file system.
-k {posix | nfs4 | all}
Specifies the type of authorization supported by the file system:
posix Traditional GPFS ACLs only (NFS V4 ACLs are not allowed). Authorization controls are
unchanged from earlier releases.
nfs4 Support for NFS V4 ACLs only. Users are not allowed to assign traditional GPFS ACLs to
any file system objects (directories and individual files).
all Any supported ACL type is permitted. This includes traditional GPFS (posix) and NFS V4
ACLs (nfs4).
The administrator is allowing a mixture of ACL types. For example, fileA may have a
posix ACL, while fileB in the same file system may have an NFS V4 ACL, implying
different access characteristics for each file depending on the ACL type that is currently
assigned.
Neither nfs4 nor all should be specified here unless the file system is going to be exported to NFS
V4 clients. NFS V4 ACLs affect file attributes (mode) and have access and authorization
characteristics that are different from traditional GPFS ACLs.
-m DefaultMetaDataReplicas
Changes the default number of metadata replicas. Valid values are 1 and 2 but cannot exceed the
values of MaxMetaDataReplicas set when the file system was created.
-o MountOptions
Specifies the mount options to pass to the mount command when mounting the file system. For a
detailed description of the available mount options, see “GPFS-specific mount options” on page
13.
-Q {yes | no}
If yes is specified, quotas are activated automatically when the file system is mounted. If no is
specified, the quota files remain in the file system, but are not used.
To activate quota management after the mmchfs -Q yes command has been issued:
1. Unmount the file system everywhere.
2. Remount the file system, activating the new quota files. All subsequent mounts obey the new
quota setting.
3. Compile inode and disk block statistics using the mmcheckquota command. Use these values
as a reference to establish realistic quota values when issuing the mmedquota and
mmdefedquota commands.
4. For default quotas:
a. Issue the mmdefedquota command to establish default quota values.
b. Issue the mmdefquotaon -d command to activate default quotas.
5. For explicit quotas:
a. Issue the mmedquota command to establish quota values.
104 GPFS: Administration and Programming Reference