Adding DMP devices to an existing LVM volume group or creating a new LVM volume group


Adding DMP devices to an existing LVM volume group or creating a new LVM volume group
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When the dmp_native_support is ON, you can create a new LVM volume group on an available DMP device. You can also add an available DMP device to an existing LVM volume group. After the LVM volume groups are on DMP devices, you can use any of the LVM commands to manage the volume groups.

To create a new LVM volume group on a DMP device or add a DMP device to an existing LVM volume group

Choose disks that are available for use by LVM.
Use the vxdisk list command to identify these types of disks.
- Disks that are not in use by VxVM
  
  The output of vxdisk list shows these disks with the Type auto:none and the Status as online invalid.
The example shows available disks.
```
# vxdisk list
```
```
DEVICE               TYPE      DISK  GROUP    STATUS
. . .
tagmastore-usp0_0035 auto:none -     -        online invalid
tagmastore-usp0_0036 auto:none -     -        online invalid
```

Create a new LVM volume group on a DMP device.

Use the complete path name for the DMP device.

# pvcreate /dev/vx/dmp/tagmastore-usp0_0035
Physical volume "/dev/vx/dmp/tagmastore-usp0_0035" successfully 
created
#
# vgcreate /dev/newvg /dev/vx/dmp/tagmastore-usp0_0035
  Volume group "newvg" successfully created
# vgdisplay -v newvg |grep Name
    Using volume group(s) on command line
    Finding volume group "newvg"
  VG Name               newvg
    PV Name               /dev/vx/dmp/tagmastore-usp0_0035s3

Add a DMP device to an existing LVM volume group.

Use the complete path name for the DMP device.

# pvcreate /dev/vx/dmp/tagmastore-usp0_0036
Physical volume "/dev/vx/dmp/tagmastore-usp0_0036" 
successfully created

# vgextend newvg /dev/vx/dmp/tagmastore-usp0_0036
  Volume group "newvg" successfully extended

# vgdisplay -v newvg |grep Name
    Using volume group(s) on command line
    Finding volume group "newvg"
  VG Name               newvg
  PV Name               /dev/vx/dmp/tagmastore-usp0_0035s3
  PV Name               /dev/vx/dmp/tagmastore-usp0_0036s3

Run the following command to trigger DMP discovery of the devices:
```
# vxdisk scandisks
```

After the discovery completes, the disks are shown as in use by LVM:

# vxdisk list

. . .
tagmastore-usp0_0035 auto:LVM   -         -    LVM
tagmastore-usp0_0036 auto:LVM   -         -    LVM

For all of the LVM volume entries, add '_netdev' to the mount options in /etc/fstab. This option ensures that these volumes are enabled after DMP devices are discovered.

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