Replacing LUNs dynamically from an existing target ID


Replacing LUNs dynamically from an existing target ID
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Dynamic Multi-Pathing (DMP) provides a Dynamic Reconfiguration tool to simplify the replacement of new LUNs from an existing target ID. Each LUN is unmapped from the host. DMP issues an operating system device scan and cleans up the operating system device tree.

Warning:

Do not run any device discovery operations outside of the Dynamic Reconfiguration tool until the device operation is completed.

In a cluster, perform the steps on all the nodes in the cluster.

To replace LUNs dynamically from an existing target ID

Stop all applications and volumes that are hosted on the LUNs that are to be removed.
If the device is in use by Veritas Volume Manager (VxVM), perform the following steps:
- If the device is part of a disk group, move the disk out of the disk group.
```
# vxdg -g dgname rmdisk daname
```
  See Removing a disk from a disk group.
- Remove the disk from the vxdisk list.
  
  In a cluster, perform this step from all of the nodes.
```
# vxdisk rm da-name
```
  For example:
```
# vxdisk rm eva4k6k0_0
```
For LUNs using Linux LVM over DMP devices, remove the device from the LVM volume group
```
# vgreduce vgname devicepath
```
Start the vxdiskadm utility:
```
# vxdiskadm
```
Select the Dynamic Reconfiguration operations option from the vxdiskadm menu.
Select the Replace LUNs option.
The output displays a list of LUNs that are available for replacement. A LUN is available for replacement if there is no open on the LUN, and the state is online or nolabel.
Select one or more LUNs to replace.
At the prompt, confirm the LUN selection.
Remove the LUN from the array/target.
Return to the Dynamic Reconfiguration tool and select y to continue the removal.
After the removal completes successfully, the Dynamic Reconfiguration tool prompts you to add a LUN.
When the prompt displays, add the LUNs from the array/target.
Select y to continue to add the LUNs.
DMP updates the operating system device tree and the VxVM device tree. The newly-discovered devices are now visible.

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Adding new LUNs dynamically to a target ID	Home	Dynamic LUN expansion