IBM Books

IBM General Parallel File System for AIX: Administration and Programming Reference

mmadddisk Command

Name

mmadddisk - Adds disks to a GPFS file system.

Synopsis

mmadddisk Device {"DiskDesc[;DiskDesc...]" | -F DescFile} [-a] [-r] [-v {yes | no} ] [-N { all | mount | NodeName[,NodeName...]} ]

Description

Use the mmadddisk command to add disks to a GPFS file system. This command optionally rebalances an existing file system after adding disks when the -r flag is specified. The mmadddisk command does not require the file system to be unmounted before issuing the command. The file system can be in use while the command is run.

Device must be the first parameter.

The -N parameter can only be used in conjunction with the -r option.

In an SP environment, ensure the new node is an active member of the virtual shared disk group. See the IBM Parallel System Support Programs for AIX: Managing Shared Disks and search on Designating nodes as IBM Virtual Shared Disk nodes.

Parameters

Device
The device name of the file system to which the disks are added. File system names need not be fully qualified. fs0 is as acceptable as /dev/fs0.

This must be the first parameter.

DiskDesc
A descriptor for each disk to be added. Each descriptor is delimited by a semicolon (;) and the entire list must be enclosed in quotation marks (' or ").

-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.

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. 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.

Logical volume use in an HACMP environment:

  1. 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.

  2. 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.

-N { all | mount | NodeName[,NodeName...] }
Specifies the nodes which should participate in the restripe of the file system after the specified disks have been made available for use by GPFS. This parameter can only be used in conjunction with the -r option.

Valid values are:

all
Indicates that all nodes in the GPFS nodeset, whether or not they have the file system mounted, should participate in the restripe of the file system. This is the default when the -N option has not been specified.

mount
Indicates that only the nodes which have the file system mounted should participate in the restripe of the file system.

NodeName[,NodeName...]
A comma-separated list of nodes to participate in the restripe of the file system.

The hostname or IP address used for a node must refer to the adapter port over which the GPFS daemons communicate. Alias interfaces are not allowed. Use the original address or a name that is resolved by the host command to that original address. You may specify a node using any of these forms:
Format Example
Short hostname k145n01
Long hostname k145n01.kgn.ibm.com
IP address 9.119.19.102

Options

-a
Specifies whether the mmadddisk command should wait for rebalancing to complete before returning. If this flag is specified, the mmadddisk command runs asynchronously and returns after the file system descriptor is updated and the rebalancing scan is started, but it does not wait for rebalancing to finish. If no rebalancing is requested (the -r flag not specified), this option has no effect.

-r
Rebalance all existing files in the file system to make use of new disks.

-v yes | no
Verify the 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 part of an existing file system.

Exit status

0
Successful completion.

1
A failure has occurred.

Security

You must have root authority to run the mmadddisk command.

In an SP environment:

  1. Verify the authentication method set for SP security services:
    1. If your authentication method is set to compatibility, Kerberos authentication is required. Issue the k4init command.
    2. If your authentication method is set to DCE, dce_login authentication is required.
    3. 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.

  2. You may issue the mmadddisk command from any node running GPFS or the CWS.
  3. If you are executing the mmadddisk command 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:

  1. 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:
    1. Proper authorization is granted to all nodes in the GPFS cluster.
    2. The nodes in the GPFS cluster can communicate without the use of a password.
  2. You may issue the mmadddisk command from any node in the GPFS cluster.

Examples

  1. In an SP environment, to create a new virtual shared disk on the physical disk hdisk48, using nodes sp1sw05 and sp1sw06 respectively as the primary and backup virtual shared disk server nodes, allowing both data and metadata, and accepting the default failure group, place this disk descriptor in a file, such as /tmp/fs1desc: 
    hdisk48:sp1sw05:sp1sw06:dataAndMetadata:
    Invoke the mmcrvsd command: 
    mmcrvsd -F /tmp/fs1desc
    The mmcrvsd command creates the virtual shared disk and rewrites the /tmp/fs1desc file in a format that can be given to the mmadddisk command: 
    mmadddisk fs1 -F /tmp/fs1desc
    The virtual shared disk is added to the default failure group of 4005.

    The system displays information similar to: 

    GPFS: 6027-531 The following disks of fs1 will be formatted on node k145n13:
    gpfs94vsd.6: size 8880128 KB
Extending Allocation Map
  12 % complete on Sat Sep  9 16:04:13 2000
  24 % complete on Sat Sep  9 16:04:18 2000
  36 % complete on Sat Sep  9 16:04:23 2000
  49 % complete on Sat Sep  9 16:04:28 2000
  61 % complete on Sat Sep  9 16:04:33 2000
  73 % complete on Sat Sep  9 16:04:38 2000
  85 % complete on Sat Sep  9 16:04:43 2000
  97 % complete on Sat Sep  9 16:04:48 2000
 100 % complete on Sat Sep  9 16:04:49 2000
GPFS: 6027-1503 Completed adding disks to file system fs1.
mmadddisk: 6027-1371 Propagating the changes to all affected nodes.
This is an asynchronous process.
  2. In an HACMP environment, to add the disk gpfslv02 to the file system fs1, use it for both data and metadata, have it belong to failure group 3, and rebalance the existing files after it is added, enter: 
    mmadddisk fs1 gpfslv02:::dataOnly:3 -r
    The system displays information similar to: 
    GPFS: 6027-531 The following disks of fs1 will be formatted on node k1455n01:
    gpfslv02: size 4390912 KB
Extending Allocation Map
GPFS: 6027-1503 Completed adding disks to file system fs1.
mmadddisk: 6027-1371 Propagating the changes to all affected nodes.
This is an asynchronous process.
Restriping fs1 ...
GPFS: 6027-589 Scanning file system metadata, phase 1 ... 
  70 % complete on Wed Aug 16 15:14:28 2000
 100 % complete on Wed Aug 16 15:14:29 2000
GPFS: 6027-552 Scan completed successfully.
GPFS: 6027-589 Scanning file system metadata, phase 2 ... 
GPFS: 6027-552 Scan completed successfully.
GPFS: 6027-589 Scanning file system metadata, phase 3 ... 
GPFS: 6027-552 Scan completed successfully.
GPFS: 6027-565 Scanning user file metadata ...
   6 % complete on Wed Aug 16 15:14:45 2000
 100 % complete on Wed Aug 16 15:14:46 2000
GPFS: 6027-552 Scan completed successfully.
Done

See also

mmchdisk Command

mmcrlv Command

mmcrvsd Command

mmdeldisk Command

mmlsdisk Command

Location

/usr/lpp/mmfs/bin

[ Top of Page | Previous Page | Next Page | Table of Contents | Index ]