Yes manually moving epsilon is feasible in a planned downtime scenario.  What about in a disaster situation - if a pair goes down unexpectedly, will epsilon me auto migrated to either of the surviving nodes? 

On Dec 3, 2015, at 4:39 PM, Gelb, Scott <scott@red8.com> wrote:

I tested on 8.3.1 and when an ha-pair is degraded, epsilon moves to the other ha-pair when one of the nodes goes down, however I would move epsilon manually to a node in the other ha-pair for this type of maintenance and not assume it will move.  Then you have 2 nodes plus epsilon and continue to serve data for the aggregates/volumes on those nodes…the data on the other ha-pair shutdown will be inaccessible and the cluster will not be in a healthy state.

 

From: toasters-bounces@teaparty.net [mailto:toasters-bounces@teaparty.net] On Behalf Of Peter Choi
Sent: Thursday, December 3, 2015 1:35 PM
To: toasters@teaparty.net
Subject: Shutting down a controller pair in a 4-node cluster.

 

Hi,

 

Please consider the following scenario, as we are conducting testing. I've done my research and received varying information from support , so I thought to get this audience's take on this.

 

Basically we have a flexpod.  

 

- 2 cabinets;

- Each cabinet consists of: CN1610, Nexus, FI, 2 x FAS8020 (cDOT 8.3.1P1), UCS blades;

- Controllers are joined together in a 4-node cluster configuration;

- Cabled in such a manner that we have controller HBA and switch port redundancy.

 

If we were to shutdown a controller pair (2 nodes that are HA partners to each other), effectively shutting down 1 of the 2 cabinets.  

 

- Will the data on the disks attached to the other two controller nodes (the surviving HA pair) still be served and accessible? 
- What happens if epsilon resides on one of the nodes that are shut down. Will it be automatically shifted to a surviving member in the cluster?

 

Thanks.