Dell POWERVAULT MD3600I - Manual (Page 86)

Modifying And Removing Host-To-Virtual Disk Mapping
You can modify or remove a host-to-virtual disk mapping for several reasons, such as an incorrect mapping or
reconfiguration of the storage array. Modifying or removing a host-to-virtual disk mapping applies to both hosts and host
groups.
CAUTION: Before you modify or remove a host-to-virtual disk mapping, stop any data access (I/O) to the virtual
disks to prevent data loss.
To modify or remove host to virtual disk mapping:
1. In the AMW, select the Host Mappings tab.
2. In the Defined Mappings pane, perform one of these actions:
– Select a single virtual disk, and select Host Mappings → LUN Mapping → Change.
– Right-click the virtual disk, and select Change from the pop-up menu.
3. In the Host group or host list, select the appropriate host group or host.
By default, the drop-down list shows the current host group or the host associated with the selected virtual disk.
4. In Logical unit number, select the appropriate LUN.
The drop down list shows only the currently available LUNs that are associated with the selected virtual disk.
5. Click OK.
NOTE: Stop any host applications associated with this virtual disk, and unmount the virtual disk, if applicable,
from your operating system.
6. In the Change Mapping dialog, click Yes to confirm the changes.
The mapping is checked for validity and is saved. The Defined Mappings pane is updated to reflect the new
mapping. The object tree is also updated to reflect any movement of host groups or hosts.
7. If a password is set on the storage array, the Enter Password dialog is displayed. Type the current password for the
storage array, and click OK.
8. If configuring a Linux host, run the rescan_dm_devs utility on the host, and remount the virtual disk if required.
NOTE: This utility is installed on the host as part of the MD Storage Manager install process.
9. Restart the host applications.
Changing Controller Ownership Of The Virtual Disk
If the host has a single data-path to the MD storage array, the virtual disk must be owned by the controller to which the
host is connected. You must configure this storage array before you start I/O operations and after the virtual disk is
created. You can change the RAID controller module ownership of a standard virtual disk or a snapshot repository
virtual disk. You cannot directly change the RAID controller module ownership of a snapshot virtual disk because the
snapshot virtual disk inherits the RAID controller module owner of its associated source virtual disk. Changing the RAID
controller module ownership of a virtual disk changes the preferred RAID controller module ownership of the virtual
disk.
During a virtual disk copy, the same RAID controller module must own both the source virtual disk and the target virtual
disk. Sometimes both virtual disks do not have the same preferred RAID controller module when the virtual disk copy
starts. Therefore, the ownership of the target virtual disk is automatically transferred to the preferred RAID controller
module of the source virtual disk. When the virtual disk copy is completed or is stopped, ownership of the target virtual
disk is restored to its preferred RAID controller module. If ownership of the source virtual disk is changed during the
virtual disk copy, ownership of the target virtual disk is also changed. Under certain operating system environments, it
may be necessary to reconfigure the multi-path driver before an I/O path can be used.
86