In this case, a group of LUNs is unmapped from the host HBA ports and an operating system device scan is issued. To add subsequent LUNs seamlessly, perform additional steps to cleanup the operating system device tree.
To remove LUNs dynamically from an existing target ID
Prior to any dynamic reconfiguration, ensure that the dmp_cache_open tunable is set to on
. This setting is the default.
# vxdmpadm gettune dmp_cache_open
If the tunable is set to off
, set the dmp_cache_open tunable to on
.
# vxdmpadm settune dmp_cache_open=on
Identify which LUNs to remove from the host. Do one of the following:
For LUNs under VxVM, perform the following steps:
Evacuate the data from the LUNs using the vxevac command.
See the vxevac(1M) online manual page.
After the data has been evacuated, enter the following command to remove the LUNs from the disk group:
# vxdg -g diskgroup rmdisk da-name
If the data has not been evacuated and the LUN is part of a subdisk or disk group, enter the following command to remove the LUNs from the disk group. If the disk is part of a shared disk group, you must use the -k option to force the removal.
# vxdg -g diskgroup -k rmdisk da-name
For LUNs using HP-UX LVM over DMP devices, remove the device from the LVM volume group.
# vgreduce vgname devicepath
Using the AVID or LUN index, use Storage Array Management to unmap or unmask the LUNs you identified in step 2.
Remove the LUNs from the vxdisk list. Enter the following command on all nodes in a cluster:
# vxdisk rm da-name
This is a required step. If you do not perform this step, the DMP device tree shows ghost paths.
Clean up the HP-UX 11i v3 SCSI device tree for the devices that you removed in step 6.
This step is required. You must clean up the operating system SCSI device tree to release the SCSI target ID for reuse if a new LUN is added to the host later.
Use VxVM to perform a device scan. You must perform this operation on all nodes in a cluster. Enter one of the following commands:
Refresh the DMP device name database using the following command:
# vxddladm assign names
Verify that the LUNs were removed cleanly by answering the following questions:
Verify that the operating system metanodes are removed from the /dev directory.
Were all the appropriate LUNs removed?
Use the DMP disk reporting tools such as the vxdisk list command output to determine if the LUNs have been cleaned up successfully.
Is the vxdisk list output correct?
Verify that the vxdisk list output shows the correct number of paths and does not include any ghost disks.
If the answer to any of these questions is "No," return to step 5 and perform the required steps.
If the answer to all of the questions is "Yes," the LUN remove operation is successful.