About setting up DMP to manage native devices


About setting up DMP to manage native devices
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You can use DMP instead of third-party drivers for advanced storage management. This section describes how to set up DMP to manage native LVM devices and any logical volume that operates on those devices.

After you install DMP, set up DMP for use with LVM. To set up DMP for use with LVM, turn on the dmp_native_support tunable. When this tunable is turned on, DMP enables support for LVM on any device that does not have a VxVM label and is not in control of any third party multi-pathing (TPD) software. In addition, turning on the dmp_native_support tunable migrates any LVM volume groups that are not in use onto DMP devices.

The dmp_native_support tunable enables DMP support for LVM, as follows:

LVM volume groups

If the LVM volume groups are not in use, turning on native support migrates the devices to DMP devices.

If the LVM volume groups are in use, then perform the steps to turn off the devices and migrate the devices to DMP.

Veritas Volume Manager (VxVM) devices

Native support is not enabled for any device that has a VxVM label. To make the device available for LVM, remove the VxVM label.

VxVM devices can coexist with native devices under DMP control.

Devices that are multi-pathed with Third-party drivers (TPD)

If a disk is already multi-pathed with a third-party driver (TPD), DMP does not manage the devices unless you remove TPD support. After removing TPD support, turn on the dmp_native_support tunable to migrate the devices.

If LVM volume groups are constructed over TPD devices, then perform the steps to migrate the LVM volume groups onto DMP devices.

To turn on the dmp_native_support tunable, use the following command:

# vxdmpadm settune dmp_native_support=on

The first time this operation is performed, the command reports if a volume group is in use, and does not migrate those devices. To migrate the volume group onto DMP, stop the volume group. Then execute the vxdmpadm settune command again to migrate the volume group onto DMP.

To verify the value of the dmp_native_support tunable, use the following command:

# vxdmpadm gettune dmp_native_support
         Tunable               Current Value  Default Value
----------------------------    ----------------    -----------------
dmp_native_support               on              off