IBM General Parallel File System for AIX: Administration and Programming Reference
Name
mmcrfs - Creates a GPFS file system.
Synopsis
mmcrfs Mountpoint Device {
"DiskDesc[;DiskDesc...]"
| -F DescFile} [-C NodesetId ]
[ -A {yes | no} ] [-B
BlockSize] [-m
DefaultMetadataReplicas] [-M
MaxMetadataReplicas] [-n NumNodes]
[-N NumInodes] [ -Q {yes | no} ] [-r DefaultDataReplicas]
[-R MaxDataReplicas] [-v {yes | no} ] [-z {yes | no} ]
Description
Use the mmcrfs command to create a GPFS file system. The
first three options must be Mountpoint, Device,
and either DiskDescList or DescFile and they must
be in that order. The block size and replication factors chosen will
affect file system performance. There is a maximum of 32 file systems
that may exist within a GPFS nodeset.
When issuing the mmcrfs command, the size of the command must not
exceed the shell limit. If the shell limit is insufficient to specify
the file system on the command line, shorten the command string by using the
-F option and specifying the disk descriptors in a file.
Upon successful execution of the mmcrfs command these tasks are
completed on all GPFS nodes:
- Mount point directory is created.
- File system is formatted.
Parameters
- Mountpoint
- The mountpoint directory of the GPFS file system.
- Device
- The device name of the file system to be created.
File system names need not be fully qualified. fs0 is as
acceptable as /dev/fs0. However, file system names must be
unique across GPFS nodesets and cannot be an existing entry in
/dev.
- -F DescFile
- Specifies a file containing a list of disk descriptors, one per
line. You may use the rewritten DiskDesc file created by the
mmcrvsd command in an SP environment or the mmcrlv command in an HACMP environment, or create
your own file, or enter the disk descriptors on the command line. When
using the DiskDesc file created by either the mmcrvsd
command or the mmcrlv command command, the values supplied on input
to the command for Disk Usage and FailureGroup are
used. When creating your own file or entering the descriptors on the
command line, you must specify these values or accept the system
defaults. A sample file can be found in
/usr/lpp/mmfs/samples/diskdesc.
- "DiskDesc[;DiskDesc...]"
- A descriptor for each disk to be included. Each descriptor is
separated by a semicolon (;). The entire list must be enclosed in
quotation marks (' or ").
Disk descriptors
The current maximum number of disk descriptors that can be defined for any
single file system is 1024. Each disk descriptor must be specified in
the form:
DiskName:::DiskUsage:FailureGroup
- DiskName
- In an SP environment, you must specify the virtual shared disk
name. For details on generating a virtual shared disk, see Specifying disk descriptors and the mmcrvsd
command. To use an existing virtual shared disk in the file system,
only the virtual shared disk name need be specified in the disk
descriptor. GPFS performance and recovery processes function best with
one disk per virtual shared disk. If you want to create virtual shared
disks with more than one disk, refer to the IBM Parallel System Support Programs for
AIX: Managing Shared Disks manual.
In an HACMP environment, you must specify the logical volume
name. For details on generating a logical volume, see Specifying disk descriptors and the mmcrlv
command. To use an existing logical volume group in the file system,
only the logical volume name need be specified in the disk descriptor.
The disk name must be set up the same on all of the nodes in the
nodeset.
Logical volume use in an HACMP environment:
- Any disk resources (volume groups and logical volumes) that will be used
by GPFS must not belong to any HACMP/ES resource group. HACMP/ES will
not be in control of these disk resources and is not responsible for varying
them on or off at any time. The responsibility to keep the disks in the
proper state belongs to GPFS in the HACMP environment. For further
information on logical volume concepts, see the AIX System Management Guide:
Operating System and Devices.
- When using single-node quorum Fibre Channel attached disks are not
supported.
- Disk Usage
- Specify a disk usage or accept the default:
- dataAndMetadata (default)
- dataOnly
- metadataOnly
- Failure Group
- A number identifying the failure group to which this disk belongs.
You can specify any value from -1 (where -1 indicates that the disk has no
point of failure in common with any other disk) to 4000. If you do not
specify a failure group, the value defaults to the server node number plus
4000. GPFS uses this information during data and metadata placement to
assure that no two replicas of the same block are written in such a way as to
become unavailable due to a single failure. All disks that have a
common point of failure, such as all disks that are attached to the same
virtual shared disk server node, should be placed in the same failure
group. All disks that are attached to the same disk adapter, should be
placed in the same failure group.
- -C NodesetId
- The identifier of the GPFS nodeset you want the file system to
belong to. If this option is not specified or a period
(.) is used for the NodesetId, the file system
belongs to the nodeset from which the mmcrfs command was
issued. To determine the nodeset of the node you are running on, issue
the mmlsnode -C . command.
In an SP environment, if this option is not specified and the
command is issued from the CWS, the command fails.
Options
- -A {yes | no}
- Specifies whether the file system is automatically mounted when the
GPFS daemon starts. The default is yes.
- -B BlockSize
- Size of data blocks. Must be 16K, 64K, 256K (the default), 512K, or
1024K (1M is also acceptable).
If you choose a block size larger than 256K, you must run mmchconfig to change the value of
maxblocksize to a value at least as large as
BlockSize. This value cannot be changed without recreating the
file system.
The maximum GPFS file system size that can be mounted is limited by
the control structures in memory required to maintain the file system.
These control structures, and consequently the maximum mounted file system
size, are a function of the block size of the file system.
- If your file systems have a 16KB block size, you may have one or more file
systems with a total size of 1TB mounted.
- If your file systems have a 64KB block size, you may have one or more file
systems with a total size of 10TB mounted.
- If your file systems have a 256KB or greater block size, you may have file
systems mounted with a total size of not greater than 200TB where no single
file system exceeds 100TB.
- -m DefaultMetadataReplicas
- Default number of copies of inodes, directories, and indirect blocks
for a file. Valid values are 1 and 2 but cannot exceed the value of
MaxMetadataReplicas. The default is 1.
- -M MaxMetadataReplicas
- Default maximum number of copies of inodes, directories, and
indirect blocks for a file. Can only be overridden by a system call
when the file has length 0. Valid values are 1 and 2 but cannot be
lower than DefaultMetadataReplicas. The default is
1.
- -n NumNodes
- The estimated number of nodes that will mount the file system. This
is used as a best guess for the initial size of some file system data
structures. The default is 32. This value cannot be changed
after the file system has been created.
- -N NumInodes
- The maximum number of files in the file system. This value defaults
to the size of the file system at creation, divided by 1M, and can be
specified with a suffix, for example 8K or 2M. This value is also
constrained by the formula:
maximum number of files = (total file system space/2) / (inode size +
subblock size)
- -Q {yes | no}
- Activates quotas automatically when the file system is
mounted. The default is no.
To install quotas after the file system has been created:
- Mount the file system.
- Issue the mmedquota command to set quota
values (see Establishing and changing quotas).
- Issue the mmquotaon command to activate
quota enforcement (see Activating quota enforcement).
- -r DefaultDataReplicas
- Default number of copies of each data block for a file. Valid
values are 1 and 2, but cannot exceed MaxDataReplicas. The
default is 1.
- -R MaxDataReplicas
- Default maximum number of copies of data blocks for a file. Can
only be overridden by a system call when the file has length 0. Valid
values are 1 and 2 but cannot be lower than
DefaultDataReplicas. The default is 1.
- -v {yes | no}
- Verify that specified disks do not belong to an existing file
system. The default is yes. Specify no only
when you want to reuse disks that are no longer needed for an existing file
system.
- -z {yes | no}
- Enable or disable DMAPI on the file system. The default is
no. For further information on DMAPI for GPFS, see IBM General Parallel File System for AIX: Data
Management API Guide.
Exit status
- 0
- Successful completion.
- 1
- A failure has occurred.
Security
You must have root authority to run the mmcrfs command.
In an SP environment:
- Verify the authentication method set for SP security services:
- If your authentication method is set to compatibility, Kerberos
authentication is required. Issue the k4init command.
- If your authentication method is set to DCE, dce_login
authentication is required.
- If your authentication method is set to NONE/std, there must be an entry
in the /etc/sysctl.mmcmd.acl file on every node in
the nodeset for the root user at every other node in the nodeset.
For further information, see the latest IBM Parallel System
Support Programs for AIX: Administration Guide, IBM Parallel
System Support Programs for AIX: Command and Technical Reference,
and RS/6000: Planning Volume 2, Control Workstation and Software
Environment manuals at www.rs6000.ibm.com/resource/aix_resource/sp_books/pssp.
Search for information on sysctl.
- You may issue the mmcrfs command from any node running GPFS or
the CWS when using the -C option.
- If you are executing mmcrfs from the CWS on a multi-partitioned
system, the SP_NAME environment variable must be properly set.
It is suggested that you use a separate window for each partition and set the
environment variable accordingly. For further information, see the IBM Parallel System Support Programs for
AIX: Administration Guide and search for understanding
system partitioning.
In an HACMP environment:
- When using rcp and rsh for remote communication, a
properly configured /.rhosts file must exist in the root
user's home directory on each node in the GPFS cluster. If you
have designated the use of a different remote communication program on either
the mmcrcluster or the mmchcluster command, you must insure:
- Proper authorization is granted to all nodes in the GPFS cluster.
- The nodes in the GPFS cluster can communicate without the use of a
password.
- You may issue the mmcrfs command from any node in the GPFS
cluster.
Examples
To create a file system called gpfs2 with a block size of 16K,
mounted on 16 nodes, accommodating an estimated 2500 files, automatically
mount it when the nodes boot up, and having a maximum replication for data and
metadata of two, although only metadata is initially replicated by default,
enter:
mmcrfs /gpfs2 /dev/gpfs2 -F /tmp/vsdsaaa -A yes -B 16k -m 2 -M 2 -r 1 -R 2
The system displays information similar to:
mmcrfs: 6027-1052 Making MMFS filesystem /dev/gpfs2
/usr/sbin/tscrfs /dev/gpfs2 -F /tmp/mmcrfs.tsdd.26160 -c 0 -f 512 -I 16384 \
-i 1024 -M 2 -m 2 -n 32 -p no -R 2 -r 1 -s roundRobin -w 0
MMFS:6027-531 The following disks of gpfs2 will be formatted on node k145n09:
gpfs0vsd: size 4399104 KB
gpfs1vsd: size 4399104 KB
gpfs2vsd: size 4399104 KB
gpfs3vsd: size 4399104 KB
gpfs8vsd: size 4399104 KB
gpfs9vsd: size 4399104 KB
gpfs10vsd: size 4399104 KB
gpfs11vsd: size 4399104 KB
gpfs16vsd: size 4399104 KB
gpfs17vsd: size 4399104 KB
gpfs18vsd: size 4399104 KB
gpfs19vsd: size 4399104 KB
gpfs24vsd: size 4399104 KB
gpfs25vsd: size 4399104 KB
gpfs26vsd: size 4399104 KB
gpfs27vsd: size 4399104 KB
gpfs32vsd: size 4399104 KB
gpfs33vsd: size 4399104 KB
gpfs34vsd: size 4399104 KB
gpfs35vsd: size 4399104 KB
gpfs40vsd: size 4399104 KB
gpfs41vsd: size 4399104 KB
gpfs42vsd: size 4399104 KB
gpfs43vsd: size 4399104 KB
MMFS: 6027-540 Formatting file system ...
Creating Inode File
28 % complete on Mon Jun 7 11:24:18 1999
54 % complete on Mon Jun 7 11:24:23 1999
79 % complete on Mon Jun 7 11:24:28 1999
100 % complete on Mon Jun 7 11:24:32 1999
Creating Allocation Maps
Clearing Inode Allocation Map
28 % complete on Mon Jun 7 11:24:40 1999
57 % complete on Mon Jun 7 11:24:45 1999
86 % complete on Mon Jun 7 11:24:50 1999
100 % complete on Mon Jun 7 11:24:52 1999
Clearing Block Allocation Map
18 % complete on Mon Jun 7 11:24:57 1999
36 % complete on Mon Jun 7 11:25:02 1999
55 % complete on Mon Jun 7 11:25:07 1999
73 % complete on Mon Jun 7 11:25:12 1999
92 % complete on Mon Jun 7 11:25:17 1999
100 % complete on Mon Jun 7 11:25:19 1999
Flushing Allocation Maps
MMFS: 6027-572 Completed creation of file system /dev/gpfs2.
MMFS: 6027-623 All disks up and ready
See also
mmchfs Command
mmdelfs Command
mmedquota Command
mmfsck Command
mmdf Command
mmlsfs Command
IBM General Parallel File System for AIX: Data
Management API Guide
Location
/usr/lpp/mmfs/bin
[ Top of Page | Previous Page | Next Page | Table of Contents | Index ]