Example of the mmvdisk command sequence

The mmvdisk command assumes that the IBM Storage Scale cluster is installed and configured properly with respect to licenses, quorum and node designations, and network connectivity. The intended IBM Storage Scale RAID recovery group server nodes must be members of the cluster.

In the case of IBM Storage Scale System 3200, the two server nodes should be properly connected to the enclosures that will provide the disks for the recovery group pair. In the case of IBM Spectrum® Scale Erasure Code Edition, the intended server nodes should each be populated with the correct number and type of disks that will make up the scale-out recovery group. In the case of IBM Elastic Storage® System 3000, the two server nodes should be properly connected to the enclosure that provides the disks for the shared recovery group.

The path to creating vdisk-based file systems with mmvdisk follows this sequence of steps:

Creating the mmvdisk node class. For a shared recovery group or for a recovery group pair, mmvdisk is used to create an mmvdisk node class for the server pair.
```
mmvdisk nodeclass create --node-class ESS01 -N server01,server02
```
For a scale-out recovery group, the mmvdisk node class is created using all of the intended server nodes (from 4 to 32):
```
mmvdisk nodeclass create --node-class NC01 -N server01,server02,server03,server04,...
```
Verifying recovery group server disk topologies. Next, mmvdisk is used to verify that the intended supported server disk topology is recognized on the node class.
```
mmvdisk server list --node-class ESS01 --disk-topology
```
Any errors in the disk topology should be recognized and corrected at this step.
Configuring recovery group servers. mmvdisk is then used to configure the mmvdisk node class as recovery group servers.
```
mmvdisk server configure --node-class ESS01 --recycle one
```
Creating recovery groups. For paired recovery groups, mmvdisk uses the mmvdisk node class to create the recovery group pair.
```
mmvdisk recoverygroup create --recovery-group ESS01L,ESS01R --node-class ESS01
```
For a shared or scale-out recovery group, mmvdisk uses the mmvdisk node class to create the single recovery group.
```
mmvdisk recoverygroup create --recovery-group RG01 --node-class NC01
```
Defining vdisk sets. With the recovery group or recovery group pair created, mmvdisk is used to define vdisk sets. The vdisk set definitions are specification templates that are sized within one or more recovery groups, which allows the disk space and server memory demands to be previewed and evaluated before any vdisk NSDs are actually created. For a recovery group pair, the vdisk sets should be defined in both recovery groups.
```
mmvdisk vdiskset define --vdisk-set vs1 --recovery-group ESS01L,ESS01R --code 8+3p --block-size 4m --set-size 50%
mmvdisk vdiskset define --vdisk-set vs2 --recovery-group ESS01L,ESS01R --code 4+2p --block-size 512k --set-size 25%
```
For a shared or scale-out recovery group, define the vdisk sets in the single recovery group.
```
mmvdisk vdiskset define --vdisk-set vs1 --recovery-group RG01 --code 8+3p --block-size 4m --set-size 50%
mmvdisk vdiskset define --vdisk-set vs2 --recovery-group RG01 --code 4+2p --block-size 512k --set-size 25%
```
As long as the actual vdisk NSDs have not been created, vdisk sets may be undefined and defined again until the attributes and disk and memory sizings are satisfactory.
Creating vdisk NSDs. When the vdisk set definitions have been satisfactorily sized, mmvdisk is used to create the actual vdisk NSDs.
```
mmvdisk vdiskset create --vdisk-set vs1,vs2
```
Creating vdisk-based file systems. Once vdisk sets are created, mmvdisk is used to create file systems that use the vdisk NSDs from one or more vdisk sets.
```
mmvdisk filesystem create --file-system fs1 --vdisk-set vs1
mmvdisk filesystem create --file-system fs2 --vdisk-set vs2
```

These are the seven basic steps that are used to create mmvdisk file systems.