Bug 1679113

With RHHI-V 1.6 support for distributed-replicate and distributed arbitrated volume and the expansion to such volume is supported. We need to remove the documentation that claims such a combination is not supported from RHHI guides


+++ This bug was initially created as a clone of Bug #1591397 +++

After speaking with Sean Murphy and Daniel Messer it was decided that this statement is inaccurate and affecting customer adoption of the product.  Please remove it in current documentation and future documentation.

1.1.1. Before you begin
Expanding the existing volumes to span across more nodes is not supported.

--- Additional comment from Red Hat Bugzilla Rules Engine on 2018-06-14 15:45:57 UTC ---

This bug is automatically being proposed for the current release of Red Hat Hyperconverged Infrastructure (RHHI) under active development, by setting the release flag 'rhhi‑2.0' to '?'. 

If this bug should be proposed for a different release, please manually change the proposed release flag.

--- Additional comment from James Radtke on 2018-06-16 12:59:13 UTC ---

The following are 2 statements in the RHHI docs which seemingly negate the possibility of expanding the initial volume deployment.

Red Hat Hyperconverged Infrastructure 1.1 - Maintaining Red Hat Hyperconverged Infrastructure
*************** ****************

CHAPTER 1. ADD COMPUTE AND STORAGE RESOURCES
Red Hat Hyperconverged Infrastructure (RHHI) can be scaled in multiples of three nodes to a maximum of nine nodes.
1.1. SCALING RHHI DEPLOYMENTS
1.1.1. Before you begin
Be aware that the only supported method of scaling Red Hat Hyperconverged Infrastructure (RHHI) is to create additional volumes that span the new nodes. Expanding the existing volumes to span across more nodes is not supported.


Red Hat Hyperconverged Infrastructure - 1.1 - Deploying Red Hat Hyperconverged
Infrastructure
*************** ****************

3.6. SUPPORT LIMITATIONS
One arbitrated replicated volume is supported as part of the initial deployment of Red Hat Hyperconverged Infrastructure (RHHI). Expanding this arbitrated replicated volume is not supported. Adding additional arbitrated replicated volumes is not supported.
Arbitrated replicated volumes are currently supported only in a replica 3 arbiter 1 configuration.

--- Additional comment from John Call on 2018-06-18 20:50:21 UTC ---

I tested volume expansion via the RHVM GUI in my lab today and it worked as expected.  I expanded a volume used for running VMs from 3 bricks to 6 bricks.  The GUI presented a warning message about potential degraded performance, see below.  I wonder if that is related to rebalance operations (which have to be triggered manually)  I used version 4.2 of RHV and 3.3u1 of RHGS

==GUI popup warning==
Add Bricks warning:
Expanding gluster volume in a hyper-converged setup is not recommended as it could lead to degraded performance. To expand storage for cluster, it is advised to add additional gluster volumes.

Are you sure you want to continue?
==END==

--- Additional comment from Laura Bailey on 2018-07-06 01:43:30 UTC ---

Sas, Sahina, I'm deferring to you on this.

My understanding has always been that the initially created volumes cannot be expanded across new nodes, and that new volumes need to be created instead.

Keep in mind that we document what QE tests, verifies, and recommends rather than what is technically possible, or we risk leading customers into bad configurations.

--- Additional comment from Sahina Bose on 2018-07-06 12:38:50 UTC ---

While volume expansion is possible - there were some corner cases where moving from replicate to distribute-replicate fails, and we do not support this mode of scaling. QE has not tested this. 
Adding needinfo on Krutika to link to the known bugs around this

--- Additional comment from Krutika Dhananjay on 2018-07-06 12:46:03 UTC ---

https://bugzilla.redhat.com/show_bug.cgi?id=1463907
https://bugzilla.redhat.com/show_bug.cgi?id=1434653
https://bugzilla.redhat.com/show_bug.cgi?id=1530146

are the ones I am aware of.

-Krutika

--- Additional comment from Laura Bailey on 2018-07-09 00:28:36 UTC ---

Thanks Krutika, Sahina.

I'm going to reach out to John, Sean, Daniel, and Ken to verify that we can close this NOTABUG.

--- Additional comment from Sahina Bose on 2018-09-25 10:42:17 UTC ---

Bug 1632144 logged to track this feature from engineering.

--- Additional comment from Laura Bailey on 2018-10-02 02:55:35 UTC ---

Thanks Sahina. Closing NOTABUG for now, and will add this back to the docs queue when the engineering feature is ready.