Description of problem: 

    AFAIK we support only replicate or distribute-replicate volume with replica 3 or arbiter with sharding. These things are not mentioned clearly in the doc.

    We should be precise and clear on what is supported and what is recommended.


This Bug has been opened to clarify and document few things :

    1) replicate or distribute-replicate volume(with and without sharding): Is this a supported volume or recommended volume. Is any other volume type supported for RHV? Only supported volume should be clearly indicated in the doc.
        As of now in the section :
             3.1. Using Red Hat Gluster Storage Volumes in the Red Hat Virtualization Manager 
         sub section: 7. Configure Storage
    """"
     For instructions on creating a Red Hat Gluster Storage Volume, see chapter 
     Red Hat Gluster Storage Volume in the Red Hat Gluster Storage 
     Administration Guide: https://access.redhat.com/documentation/en-
     us/red_hat_gluster_storage/3.3/html/administration_guide/chap-
     red_hat_storage_volumes.
    """"

   We directly point to a section in RHGS admin guide which discusses all types of volumes.

    2) Replica 3 or replica 3 with arbiter: Is this a support requirement or recommendation? 
       Current doc is a bit confusing and we do not have a strict guidance here.

      In Section 2.1. Prerequisites : 

       """
 
         To reduce the risk of split-brain conditions developing in the cluster, 
         Red Hat requires three-way replication when using Red Hat Gluster 
         Storage with Red Hat Virtualization. Three-way replication is provided 
         by three-way replicated volumes (replica 3), three-way distributed 
         replicated volumes (replica count 3), and arbitrated replicated and 
         distributed arbitrated replicated volumes (replica 3 arbiter 1).
       """

      As this is mentioned under Prerequisites, it gives a sense that this is a mandatory requirement. but we have mentioned same in section: Chapter 6. Recommended Best Practices and Troubleshooting and 3.1. Using Red Hat Gluster Storage Volumes in the Red Hat Virtualization Manager (7. Configure Storage) as well.

      A recommended practice cannot be a prerequisite or vice-versa. 

    3) What should be support statement for sharding: As of now sharding I guess is only supported for RHV use case but I don't see any mention of in our RHV[1] doc. Is this mandatory? If yes, what about existing volumes?


[1] https://access.redhat.com/documentation/en-us/red_hat_gluster_storage/3.3/html-single/configuring_red_hat_virtualization_with_red_hat_gluster_storage