I am not familiar with the specific volume/device names in your example, and to me, your question seems ambiguous. could you try to restate the question in more specific terms?
If you are asking about sizing and composition of filesystems for splunk installation home and/or index locations, this is largely a matter of preference, policy and perhaps to a greater extent, your indexing requirements.
The following are good starting points with regards to index/installation storage requirements:
http://docs.splunk.com/Documentation/Splunk/6.2.1/Installation/SystemRequirements (minimum of 5GB recommended for basic splunk install)
http://docs.splunk.com/Documentation/Splunk/latest/Capacity/HowSplunkcalculatesdiskstorage
