HP P6000 Replication Solutions Manager User Guide (T3680-96089, October 2012)

Dynamic capacity management
Dynamic capacity management overview
DC-Management provides you with the capability to extend (increase) or shrink (decrease) the size
of a host volume without disrupting host I/O. This gives you greater control over the size of host
volumes as your system storage requirements change.
If a host volume is nearing capacity, you can extend the size of the volume to avoid the situation
that occurs when a host volume reaches its full capacity. If a host volume has too much capacity
allocated to it, you can shrink the size of the volume, freeing up the unused capacity for other
applications.
DC-Management can be implemented manually or automatically.
• Manual DC-Management enables you to immediately change the volume size. The new size
remains in effect until you manually reset it again.
• Automatic DC-Management policies enable you to specify the threshold at which you want
the size of the volume to be changed. RSM monitors the capacity of the host volume and
automatically changes the size when the specified threshold is reached. You can set e-mail
notification alerting you when a volume has been resized. You can also control the time during
which the policy is enforced.
NOTE: The policy threshold is checked against the current size of the host volume during
each automatic storage refresh cycle (default 30 minutes). Therefore, even if the current size
of the host volume exceeds the set threshold, the earliest the policy will be triggered is at the
next refresh cycle. You can also manually invoke a global refresh, which may trigger a policy
as well.
TIP: To help you evaluate your storage and use DC-Management effectively, you can analyze
the current host volume capacity utilization. For more information on enabling this feature, see
Page 119.
DC-Management operation
NOTE: During a resize operation, DC-Management communicates with both the RSM host agent
and HP P6000 Command View. It is necessary to have both of these components installed to
implement DC-Management on a host.
When resizing the host volume file system, DC-Management communicates with the RSM host
agent running on the enabled host. The Windows RSM host agent uses the Windows Virtual Disk
Service (VDS) to resize the file system.
When resizing a virtual disk, DC-Management communicates with HP P6000 Command View,
which processes virtual disk resize requests and passes them to the array, where the resize operation
is implemented.
Because it is communicating with both the array and the host operating system, DC-Management
can coordinate the interaction between the file system and the underlying virtual disk during a
resize operation. This ensures you do not change the size of one component without making the
necessary changes to the other as well. And you can make the necessary changes in a single step
using RSM.
138 Host volumes