HP 3PAR StoreServ Cluster Extension Software Administrator Guide (5697-2442, July 2013)

TIP: Archive the log files before deleting them.
Hyper-V Live Migration log entries
In the HP 3PAR StoreServ Cluster Extension log file (clxmscs.log), live migration messages
include the prefix CLX_LM to help you differentiate live migration issues from HP 3PAR StoreServ
Cluster Extension log messages.
For example:
[10/12/09 20:13:02][2136][CLX_LM: CLXVMDISK04-App01][INFO] CLX detected
that Live Migration for VM "Virtual Machine VM04" has begun.
[10/12/09 20:13:02][2136][CLX_LM: CLXVMDISK04-App01][INFO] CLX started
gathering VM "Virtual Machine VM04" specific storage information.
Virtual Machine Management hosted on a Cluster Shared Volume on
Windows Server 2012
Cluster Shared Volumes of Windows Server 2012, support virtualized workloads to create virtual
machines on Cluster Shared Volumes in the Failover Cluster Manager. These VMs are the highly
available virtual machines as these are managed by the Failover Cluster.
CSV Disk resource can be owned by one cluster node whereas highly available VMs which are
created on the CSV disk can be owned by the same cluster node or any other cluster node. The
node which owns the CSV disk resource is called as the co-ordinator node. In a multi-site storage
array replicated environment, clustering of nodes is spread across the datacenter. For non CSV
disks, the application role like VM role contains the application resource, disk resource and the
CLX resource together, which means that in whichever cluster node the disk resource is online, the
application resource like VM resource would be online too. Therefore, the entire application role
like VM role containing the application resource, disk resource and the CLX resource together
would be owned by a cluster node. With the CSV feature in place, the CSV disk can be owned
by any cluster node and highly available VMs which are created on the CSV disk running on the
same cluster node or the different cluster node as that of the CSV.
If the highly available VMs are running on a cluster node which is in a different datacenter then
the VMs will run in the redirected-access mode. This is because, the replicated disk in the datacenter
where VM is running is usually presented to the cluster node as read-only on the storage array.
Which means the I/O operations of the VMs on to the CSV disk is carried over the IP network to
the coordinated node in the other datacenter and the coordinated node will take care of committing
the I/O to the disk. Due to this, VMs may incur a performance penalty especially if the distance
between the datacenter is long. This is where the CLX VM management feature plays a role.
The CLX for VM management ensures that the highly available VMs and the coordinated node of
the CSV disk are always running in the cluster nodes of the same datacenter.
NOTE: A new cluster resource type called “Cluster Extension 3PAR for VM Management” is
introduced to support the VM management in a cluster. This resource type is available only on
Windows Server 2012 or Windows Server 2012 Server Core.
If you do not need VMs running on a CSV disk which is in the redirected access mode, then you
must configure resources of type "Cluster Extension 3PAR for VM Management" in the corresponding
VM role.
Steps to configure CLX feature for VM Management functionality for a highly available VM created
on a CSV disk:
1. Create a CSV disk in the Failover Cluster Manager. The newly created CSV disk should be
managed by the CLX to do storage failover. The CSV role in which the CSV disk is residing
is not visible in the Failover Cluster GUI.
46 Configuring HP 3PAR StoreServ Cluster Extension