Unity Datastore creation takes long time

Hi!

Since two months ago we having some issues with create datastore task from Unity GUI.
This task takes long time (Usually completed with problems). Until almost 2 hour for 10Gb Datastore, for example.

Our VMWare platform use native multipath.
At SAN level our brocade switches have 4 paths (2 zones by each SP).

We don't know that others details we can check.
Last month we updated some firmware disks but I understand that it hasn`t connotation.

What other checking could we do?

Many thanks in advance.

Unity Sofware Version : 4.3
Model : 450F