A host side migration between arrays can be a nerve racking task especially when you come across issues. Data loss is a constant fear in the back of your mind and what is your fail-back plan should you need to execute it. During a PowerPath migration, I learned the hard way that a host side copy of the boot-from-san lun is NOT supported. After setting up the migration and upon the sync command the Windows machine froze to a halt until it went offline.
After troubleshooting it was clear that the EMC PowerPath Migration Enabler Service needed to be disabled for the Windows machine to fully boot. After enabling EMC PowerPath Migration Enabler after the host was booted would immediately cause the Windows host to go unresponsive and hard power cycle was the only fix.
I could not start the PowerPath Migration Enabler service to abort the session since it would immediately freeze the server and secondly I was unable to uninstall PowerPath Migration Enabler since there was a session pending. I was in a pickle!
After a support ticket with EMC, the resolution requires you to manually remove the PowerPath Migration Enabler database and keys within the registry. After preforming a few deletions then you will be able to star the service successfully without freezing your server and with no active sessions going.
- Delete the UMD by deleting the files from C:\Program Files\EMC\PPME\db*.*
- Delete the all subkeys with Prefix “dm_” EXCEPT for dev_conf under, HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\EmcPowerPath\KMD_*.
The Keys would be dm_ac, dm_control_io_to_clones, dm_funnel_io, dm_wc.
- Reboot.