How to enable Veritas Dynamic Multi-pathing and disable AIX MPIO Multipathing for array devices using vxmpio utility

Problem

To use Veritas Dynamic Multi-pathing (DMP) with AIX disk devices, the AIX native multi-pathing driver (MPIO) must be disabled for those devices, so DMP can then claim and control the paths to the device.

This is usually accomplished by installing a software package from the specific array vendor that will remove MPIO definitions from the AIX ODM. Some devices do not have vendor supplied Non-MPIO ODM definitions to disable MPIO. This utility is for removing the MPIO definitions for those devices.

The vxmpio utility controls whether the specified type of storage array is controlled by MPIO or is claimed under the Veritas Dynamic Multi-Pathing driver.

Use the vxmpio utility to disable or enable MPIO for devices with the specified product ID (pid). You must reboot the system for the changes to take effect. When you disable MPIO, the specified devices are claimed under the Veritas Dynamic Multi-Pathing driver after the reboot. When you enable MPIO, the specified devices are removed from Veritas Dynamic Multi-Pathing control and claimed under MPIO.

Error Message

Unable to place disk device under DMP control due to already claimed by MPIO. No vendor supplied non-ODM definitions available.

Cause

The issue is caused if the disk devices are already claimed by vendor specific drivers. 

Solution

Use the vxmpio utility using the reference manual from  https://sort.veritas.com/public/documents/vif/7.3/aix/manualpages/html/man/volume_manager/html/man1m/vxmpio.1m.html for disabling MPIO for any array without requiring vendor specific ODM predefines 

This is an example of how to disable MPIO control of disks on a storage using vxdmpio

For this example, we will be modifying control of hdisk9 which resides on SAN-VC.

a) Check the available disks with vxdisk -e list

# vxdisk -e list
DEVICE       TYPE           DISK         GROUP        STATUS        OS_NATIVE_NAME   ATTR
disk_0       auto           -             -            LVM          hdisk0           -                                                         
disk_1       auto           -             -            LVM          hdisk1           - 
...
san_vc0_9    auto:cdsdisk   -             -            online       hdisk9           -

b) Verify that a disk is under MPIO control at the Operating System level.

# lscfg -vl hdisk9
hdisk9 U9179.MHD.06B94ER-V86-C5-T1-W500507680140C156-L0 MPIO IBM 2145 FC Disk

Manufacturer................IBM
Machine Type and Model......2145
ROS Level and ID............30303030
Serial Number...............2145
Device Specific.(Z0)........0000063268181002
Device Specific.(Z1)........
Device Specific.(Z2)........
Device Specific.(Z3)........

NOTE: MPIO is included in the description above.

To turn off MPIO for disks on the SAN-VC, it is necessary to identify the disks by the PID of the storage array.

In this case, SAN-VC storage has the identifier 2145.

c) Turn off MPIO control of disks on the SAN (reboot may be required)

 # /etc/vx/bin/vxmpio disable pid='2145'
Running bosboot ..
trustchk: Verification of attributes failed: /usr/sbin/mknod: mode

bosboot: Boot image is 61468 512 byte blocks.
VxVM vxmpio INFO V-5-2-5828 Please reboot the machine to disable MPIO support for 2145

# shutdown -Fr now

d) Verify after reboot, MPIO is now disabled for this storage.

After the reboot, the command for the disk at OS level should no longer show MPIO in the description output.

 # lscfg -vl hdisk9
hdisk9 U9179.MHD.06B94ER-V86-C5-T1-W500507680140C156-L0 IBM 2145 FC Disk