I saw following point on Technet article about RBS.
The local FILESTREAM provider is supported only when it is used on local hard disk drives
or an attached Internet Small Computer System Interface (iSCSI) device.
You cannot use the local RBS FILESTREAM provider on remote storage devices such as network attached storage (NAS).
It looks like that we cannot use FILESTREAM on Failover Cluster because to setup Failover Cluster we need to have NAS. But then the NAS is made available locally for Failover Cluster so FILESTREAM should work right?
Found another article which talks about setting up FILESTREAM on Failover Cluster so I am a bit confused.