Convert PowerPath to MPIO with alt_disk OS Patching on AIX

This procedure describes how to migrate from EMC PowerPath-managed storage devices (hdiskpowerX) to AIX native Multipath I/O (MPIO) devices (hdiskX) using the alternate disk copy (alt_disk_copy) method — while simultaneously performing AIX OS patching or upgrades.

By using alt_disk_copy, all changes are made on a clone of the root volume group (rootvg), ensuring that the production environment remains intact until the system reboots from the alternate disk.

This is the safest and most efficient method to migrate to MPIO and apply OS updates in a single controlled maintenance window.

• Safely remove EMC PowerPath software and drivers
• Install native MPIO drivers for EMC storage
• Apply AIX OS patches or TL/SP upgrades on the alternate disk
• Validate functionality before switching production boot

On AIX systems connected to Dell EMC (Symmetrix/VMAX/PowerMax) storage:

• Disks appear as hdiskpowerX when managed by EMC PowerPath
• Disks appear as hdiskX when managed by AIX MPIO

Convert PowerPath to MPIO Disk With alt_disk OS Patching on AIX

1. Backup your system (mksysb) and copy software to NIM server

Mount NFS share /backup and take mksysb backup

# mount nfserver01:/backup  /backup

Create a system backup image with mksysb including disk layout and volume groups:
# mksysb -ieX /backup/$(hostname)_$(date +%m%d%Y)
Copy Dell EMC installation files to NFS server (adjust paths & hostnames):
# cd /software/EMC/
# scp DellEMC.AIX.6.X.X.X* server2:/software/EMC/

2. Identify target alternate disk and prepare for alt_disk_copy
Fix PowerPath root device setup (ensures proper rootvg device):
# pprootdev fix
Identify disks in rootvg:
# lspv | grep rootvg
Reduce the disk from rootvg for MPIO convertion

# powermt display dev=hdiskpowerX
# unmirrorvg rootvg hdiskpowerX
# reducevg -df rootvg hdiskpowerX
# chpv -c hdiskpowerX
If altinst_rootvg present then remove alternate rootvg from the server:
# alt_rootvg_op -X altinst_rootvg

Remove PowerPath device from target disk (replace hdiskpowerX with your device):

# powermt display dev=hdiskpowerX
# powermt remove dev=hdiskpowerX
# rmdev -dl hdiskpowerX
# chdev -l hdiskX -a pv=clear
Verify the bootlist is set to normal mode:
# bootlist -om normal

3. Convert PowerPath to native MPIO without OS patching
Copy rootvg to alternate disk:
# alt_disk_copy -d hdiskX -P1
Stop PowerPath services inside the alt rootvg environment:
# chroot /alt_inst/etc/rc.aget stop
Confirm EMC PowerPath installation:
# chroot /alt_inst /usr/sbin/lslpp -l | grep EMCpower
Uninstall EMC PowerPath package:
# chroot /alt_inst /usr/sbin/installp -u EMCpower
Remove PowerPath registration file (if present):
# chroot /alt_inst /usr/sbin/rm /alt_inst/etc/emcp_registration
Install native MPIO packages (adjust file names as needed):
# chroot /alt_inst /usr/sbin/installp -agXYd /tmp/EMC.Symmetrix.aix.rte /tmp/EMC.Symmetrix.fcp.MPIO.rte
Verify installed EMC packages (now with MPIO):
# chroot /alt_inst /usr/sbin/lslpp -L | grep EMC

4. OS Patching on the alt_disk_copy image
Mount the NFS server containing LPP sources:
# mount server1:/export/lpp_source/lpp_7300-03-01 /mnt
Remove any unwanted efix patches:
# chroot /alt_inst /usr/sbin/emgr -P
# chroot /alt_inst /usr/sbin/emgr -r -L <efix_Name>
Commit OS image update:
# chroot /alt_inst /usr/sbin/installp -c all
Verify package consistency:
# chroot /alt_inst /usr/bin/lppchk -vm3
Update Technology Level or Service Pack as needed:
# alt_disk_copy -d hdiskX -P23 -l /export/lpp_source/lpp_7300-03-01 -b update_all
Validate OS level and patch status on the alt disk:
# alt_rootvg_op -W -d hdiskX
# chroot /alt_inst /usr/bin/oslevel -s
# chroot /alt_inst /usr/bin/oslevel -sl 7300-03-01-2520
# chroot /alt_inst /usr/sbin/instfix -i | grep ML
# chroot /alt_inst /usr/sbin/instfix -i | grep SP
# chroot /alt_inst /usr/bin/lppchk -vm3
Sleep the alt rootvg disk:
# alt_rootvg_op -S -d hdiskX

Set the boot order 

# bootlist -m normal hdiskX

5. Reboot the system (during maintenance window)
# shutdown -Fr

6. Verify conversion from PowerPath to native MPIO
Check that PowerPath disks (hdiskpower) no longer exist:
# lspv | grep hdiskpower    --- Should show no output
Check installed EMC packages reflect MPIO:
# lslpp -al | grep EMC
Verify that no PowerPath-defined disks remain:
# lsdev -Cc disk | grep Defined    --- Should show empty or no PowerPath disks
Configure tunables for MPIO devices (adjust as needed):
# for i in $(lsdev -Cc disk | grep -i EMC | awk '{print $1}')

do
chdev -Pl $i -a reserve_policy=no_reserve
chdev -Pl $i -a algorithm=round_robin
chdev -Pl $i -a hcheck_interval=60
done

7. Final reboot to apply all settings
# shutdown -Fr

8. After reboot validate the server:

# oslevel -s  # check os level

# df -g     # check mount point

# lssrc -s <service name>  # check services

If its cluster the 

PowerHA cluster status check:

# lssrc -ls clstrmgrES 
# clRGinfo

GPFS Cluster status check:

# mmgetstate -aL