I need a clarification regarding MW Group replication. Assume that I have two MW groups with six servers in each group (MW GROUP HUB is already set in both groups). If I want to replicate these two groups, which approach should I follow?
Your peer Sriraman already opened a support ticket with us regarding the same inquiry. I suggest you touch base with him if there are no further comment on this post from other community members.
Updated support case 00912134 that Sri opened on this with:
There are no drawbacks to either approaches except in (1), there are more files to maintain/move around while in (2), there are less.
To confirm, I just tested your use case in my lab and both produces the same results when I test MW replication. So you can go with either style of setup and it will be the same. Hope this helps to make the decision process little easy as to which approach you want to pursue.
Thanks for your confirmation. This will definitely help us.
Is there a reason that you need to configure a "HUB". If you define groups with a defined Hub, and the hub server is down, then you will not be replicating until the Hub is available or you manually reconfigure another server in the group as the Hub. I think it may be better (I prefer ) to not define a specific hub, and let the MW Groups designate the hub.
so what's the benefit to use a group hub when the hub can be down, and you have to manually recover it?
I have a second question - Why do you have so may CA Directories defined in your environment? I know that in some cases the environment dictates, but the fewer servers (simpler) is better. Typically, a few servers per datacenter are enough to handle a very large amount of traffic.
For first question : We are using a HUB as it has been mentioned as a recommended way for MW group replication by CA in the below link.
Multiwrite Groups Hubs - CA Directory - 12.6 - CA Technologies Documentation
For second question : Actually, it is not our exact setup, that's the reason why I have used the term "Assume". I thought questioning with multiple servers, will bring clear picture/more impact for each approach.