File share high-availability can be provided via Distributed File System (DFS). For a step-by-step configuration guide for Windows Server 2008 DFS, see http://technet.microsoft.com/en-us/library/cc732863(WS.10).aspx.
When Lync components are being deployed to the file share, Topology Builder requires that the administrator that is deploying the topology have full Administrator access to the file share. The Lync Topology Builder uses NTFS file permissions to provide ACLs to the folders. Make sure that the account being used to deploy the topology has these permissions.