Powerpath Migration enabler (PPME) is one of the greatest migration tools used by EMC Customers. The software is considered an add-on to EMC mutipathing software Powepath. It is compatible with AIX, Windows, Linux,VMware etc.. . It is a host based migration tool that allows the migrations between logical volumes resides on EMC or non-EMC Arrays.
With the release of Powerpath 5.7 Sp1, EMC Engineering introduced a new cool feature for Microsoft clusters (MSCS) migrations. A new command was introduced called “powermigcl”. This command is responsible for managing the migration handles for 2008 and 2012 Cluster setups.
I will show you how to perform the migration online using this new command, There is no need to take the cluster resources offline or even shutdown the passive node like we used to do in earlier releases.
So in my setup here I have 2 W2k12 R2 cluster nodes hosting SQL 2012 database. My logical source volumes are mounted on thick RAID-5 devices while my target volumes are thin devices. All volumes are presented from Symmetrix VMAX array running code 5876.
I will use PPME hostcopy so I presented 2 new devices of size 240GB and 256Gb (larger than my source device) and I will migrate the 2 volumes used for SQL DB.
From Failover cluster manager:
I will need to check the disks presented to my cluster node using diskpart.
So in my case, Disk1 (SQL1) and Disk2( SQL2) are my source disks while Disk12 and Disk13 are the targets disks.
It is really important to check if Powerpath migration enabler is licensed. To check that, you run powermt check_registration command:
Capabilities: All, means that all Powerpath capabilities are licensed including PPME.
Capabilities: Multipathing, means that Powerpath multipathing is the only licensed component..
Now, let’s go for the migration using powermig command:
1- Powermig help
2- List Cluster resource groups.
3- Configure one of your cluster resources group for migration
4- Confirm that the Cluster resource group is configured.
Now you will notice that new cluster resources are added named PPME_<Disk_resource_name> into your configured cluster resource group and each Disk_recource is dependent on the PPME resource.
5- Now, let us setup the migration handles for the 2 cluster disks in my cluster resource group SQL Server.
Please note that –cluster switch should be used otherwise you will have error 90 (mentioned in EMC KB# 169124 article).
6- Start the migration
7- Monitor the progress of the migration
8- After the syncing is complete you will find the migration state changed to sourceSelected
9- There is no selectTarget option with powermigcl migrations so you will need to commit the migrations immediately.
10- Once the handles are committed, It’s time to check if the migration is completed from disk end so launch diskmgmt.msc , rescan then extend Disk 1.
11- To finish the migrations we will need to clear up the handles and unconfigure the cluster group.
Now your cluster migrations are completed online with no outage 🙂
- During the migration, new cluster resources are created and added as dependent disk resources. In W2k8 and W2k12 adding or removing resource dependency is done online without taking the resource offline. In w2k3 clusters, the resource will be taken offline to add or remove the dependency.(powermigcl is not supported with W2K3 migrations but this is a known issue with W2K3 cluster setups).
- PPME keeps a shared database between the cluster nodes. This database is stored by default in C:\Program Files\EMC\PPME\db\. These files should not be touched unless EMC support recommends doing so.
- Make sure that you run the migrations from a single node so avoid failover your cluster resources during the migrations. This will impact your migrations.
- No need to shut down the passive node during the migrations.