Should I expand Storage Pool or create another new one ?

Hi,

We just add another 5 HD to our CX4-240 SAN.

Currently, there is a Storage Pool with 10 HD and is dedicated to a Windows File Server.

After adding the additional space, we would like to allocate half of newly added space to File Server and the remaining free space for vSphere Cluster.

If I expand the existing Storage Pool, can I create a LUN in it that can be provisioned to vSphere Cluster.  I am new to Storage Pool and the existing one is created by a consultant before.  I have experience with RAID Groups.

Thanking you in anticipation.