mmvdisk command

Availability

Available on all IBM Spectrum Scale editions.

Description

The mmvdisk command is an integrated command suite for IBM Spectrum Scale RAID. It greatly simplifies IBM Spectrum Scale RAID administration, and encourages and enforces consistent best practices with regard to server, recovery group, vdisk NSD, and file system configuration.

The mmvdisk command can be used to manage new IBM Spectrum Scale RAID installations from the start, and existing IBM Spectrum Scale RAID installations can be converted to enable mmvdisk management. Any and all existing non-mmvdisk recovery groups in a cluster must be converted to mmvdisk management before mmvdisk can be used to create new recovery groups in the cluster.

The mmvdisk command and the legacy IBM Spectrum Scale RAID administration commands are incompatible. For example, if a recovery group is managed by mmvdisk, pdisk replacement must be performed using mmvdisk pdisk replace, since mmchcarrier will refuse to run against an mmvdisk recovery group. Conversely, mmvdisk pdisk replace will refuse to run against an existing recovery group that has not been converted to mmvdisk management, and mmchcarrier must be used with the unconverted recovery group.

The mmvdisk command structures IBM Spectrum Scale RAID around node classes, servers, recovery groups, vdisk sets, and file systems.

An mmvdisk node class contains the set of servers responsible for a recovery group pair. The IBM Spectrum Scale RAID configuration parameters for the servers are maintained under the umbrella of the node class, and the two recovery groups in the pair are also associated with the node class.

File system vdisk NSDs are managed collectively as members of vdisk sets. A vdisk set is a collection of vdisk NSDs with identical attributes from one or more recovery groups. Each recovery group included in a vdisk set contributes one member vdisk NSD. A vdisk set is managed as a unit: All member vdisk NSDs of a vdisk set must belong to the same mmvdisk file system. Defining a vdisk set across multiple recovery groups helps to ensure that a file system is balanced using identical vdisk NSDs from the recovery groups in the vdisk set.

An mmvdisk file system is an IBM Spectrum Scale RAID file system constructed from one or more vdisk sets. It is possible for an mmvdisk file system to contain non-vdisk NSDs, but the vdisk NSDs must all be members of vdisk sets, and non-vdisk and vdisk NSDs can not reside in the same file system storage pool.

In addition to the management structure provided by node classes, servers, recovery groups, vdisk sets, and file systems, mmvdisk also provides an interface to list and replace recovery group pdisks and to list individual vdisks.

The mmvdisk nodeclass command manages mmvdisk recovery group server node classes.

The mmvdisk server command manages mmvdisk recovery group servers.

The mmvdisk recoverygroup command manages mmvdisk recovery groups.

The mmvdisk vdiskset command manages mmvdisk vdisk sets.

The mmvdisk filesystem command manages mmvdisk file systems.

The mmvdisk pdisk command manages mmvdisk recovery group pdisks.

The mmvdisk vdisk command lists individual recovery group vdisks.

Parameters

An mmvdisk command has the form mmvdisk Noun Verb [Parameters]. For example, mmvdisk nodeclass list, without any parameters, will list all the mmvdisk node classes in the cluster.

The verbs are functions to be performed specific to a noun, and will always include list. Other possible verbs are: create, add, delete, and change.

After the noun and the verb, additional parameters might be required or optional, can occur in any order, and are always introduced with option flags. The vast majority of option flags are of the form --option-name and might or might not take following arguments.

Depending on the context, when it is possible to list multiple comma-separated objects as the argument to an option flag, the keyword all can often be used as shorthand for listing all objects of a type. For example, --vs all can be used to specify all vdisk sets. The individual command usage statements will indicate this with a --vdisk-set {all |VsName [,VsName...]} syntax diagram.

When a command will delete (or undefine, in the case of vdisk sets) an object permanently, mmvdisk will warn the user by prompting for confirmation. In these cases, the prompt can be bypassed and answered in the affirmative with the --confirm option.

mmvdisk will also warn the user and prompt for confirmation before performing potentially long-running commands. There is no option to bypass the prompt in the case of long-running commands.

Exit status

0

Successful completion.

nonzero

A failure occurred.

Security

You must have root authority to run the mmvdisk filesystem command.

The node on which the command is issued must be able to execute remote shell commands on any other node in the cluster without the use of a password and without producing any extraneous messages.

See also

See also the following IBM Spectrum Scale RAID: Administration topics:

Location