Daniel Nashed's Blog

Using Server Groups for Domino Replication

One of the lesser-known features in Domino server-to-server replication is that the Destination Server field in a Connection document does not have to contain a single server name. Instead, it can reference a Server Group.
According to the Domino documentation:

"You can also specify a Group name that contains server names so that the Source server replicates with each server listed in the group you specify.
To do this, you create a group that contains servers only, and specify 'Servers only' as the group type. The group cannot contain the names of other groups of servers."
https://help.hcl-software.com/domino/14.5.1/admin/conf_schedulingservertoserverreplication_t.html


At first glance this looks like an elegant way to simplify replication topologies.

A Simple Example

Instead of creating individual Connection documents like this:
ServerA --> ServerB
ServerA --> ServerC
ServerA --> ServerD

you can create a group:

---

Source Server: ServerA
Destination Server: ReplicationTargets

ServerB
ServerC
ServerD

---

and configure a single Connection document:

Domino will iterate over every server in the group and establish replication entry for each member.
This can significantly reduce the number of Connection documents that need to be maintained, especially in hub-and-spoke environments.

Requirements

There are a few rules that are easy to overlook:

• The group type must be Servers only.
• Nested groups are not supported.

The Hidden Catch

During testing we ran into an important limitation that is not immediately obvious from the documentation.
The group approach works well only if Domino can determine how to reach every destination server automatically.

That generally means:

• All servers are on the same Notes Named Network, or
• Domino can determine the network path without requiring server-specific addressing information.

If a destination server requires a dedicated network address, custom traget port, or other server-specific connection parameters, things become more complicated.


Why?

A Connection document that targets a group can only contain one set of connection parameters.
There is no way to specify different TCP/IP addresses or network information for each server in the group.
Once replication is initiated via the group Connection document, the server-specific Connection documents are apparently not consulted for network addressing.


When It Works Well

Using server groups is a great fit for environments such as:

• Servers on the same LAN
• Well-connected Notes Named Networks
• Replication where no explicit network addresses are required
• Hub servers that periodically contact many similarly configured servers
   

• Comments [0]