PowerPath for Windows: Removing Migration Enabler UMD and KMD driver context

PowerPath for Windows 7.2 and later contain an internal command to remove the user mode context and the kernel mode context from driver parameterization in one command. A reboot is mandatory after executing the command.

STEP 1

To remove the UMD and KMD context, run:

CMD C:\>powermig nodecleanup

Ensure that all options to recover, abort and cleanup existing migrations are tried before trying this nodeCleanup command. Also, a host reboot is needed to complete all the steps of this command properly. Do you still want to continue? [yes]/no:

Answer 'y' to the question. The command responds as follows:

NOTE: Host reboot is needed for the cleanup to take effect. Also, delete the backed up KMD registry keys (cleanup_*) and PPME\db.old folder before running the command again.

STEP 2

Reboot the host. This concludes the core intervention part. At this point you can bring back the cluster, and so on.

STEP 3

The nodecleanup command only moves the control structures out of the way. It does not delete them. After the reboot, you must remove the renamed UMD and KMD structures. This can be done online. A second reboot is not necessary.

1. Remove the UMD context

From C:\Program Files\EMC\PPME, remove db.old.

C:\Program Files\EMC\PPME>dir
Volume in drive C has no label.
Volume Serial Number is 6A65-4A7A

Directory of C:\Program Files\EMC\PPME

12/11/2024  12:31    <DIR>          .
12/11/2024  12:31    <DIR>          ..
12/11/2024  13:13    <DIR>          db
12/11/2024  12:31    <DIR>          db.old <- Remove this directory
               0 File(s)              0 bytes
               4 Dir(s)  47,120,658,432 bytes free

2. Remove the KMD context

In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\EmcPowerPath\KMD_0, or HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\EmcPowerPath\KMD_1 respectively, delete all "cleanup_*" keys.

Example

Remarks

• The nodecleanup command addresses the driver context only. You still must remove the PPME cluster resource.
• You may have to save the UMD and KMD content elsewhere before removing.
• This command is meant to provide procedural assurance in an emergency situation. If you are uncertain about the consequences, contact Dell Technical Support first to discuss other options.
• The server MUST be rebooted after the nodecleanup action.

Expected Error Messages

• Powermig nodecleanup fails to run when run a second time, because the UMD context backup was not removed.

When you run the nodecleanup command a second time and you have not removed the UMD context, the command fails with PPME error(119): UMD DB cleanup failed.

Example

PS C:\> powermig nodecleanup

Ensure all options to recover, abort and cleanup existing migrations are tried before trying this nodeCleanup command. Also, a host reboot is needed to complete all the steps of this command properly. Do you still want to continue? [yes]/no: y

PPME error(119): UMD DB cleanup failed

Fix

db.old still exists. Run STEP 3-1 above.

• Powermig nodecleanup fails to run when run a second time, because the KMD context backup was not removed.

When you run the command a second time and you have not removed the KMD context, the command fails with PPME error(118): KMD Registry cleanup failed.

Example

C:\Program Files\EMC\PPME>powermig nodecleanup

Ensure all options to recover, abort and cleanup existing migrations are tried before trying this nodeCleanup command. Also, a host reboot is needed to complete all the steps of this command properly. Do you still want to continue? [yes]/no: y

PPME error(118): KMD Registry cleanup failed

Fix

The cleanup values in KMD* still exist. Run STEP 3-2 above.