Database Reference
In-Depth Information
Like the previous example, the
secondary
node in
Machine 2
cannot become
primary
because the configuration of this node defines it as a priority 0 member.
The following is a sample configuration for a priority 0 member:
{
"_id" : <num>,
"host" : <hostname:port>,
"priority" : 0
}
Utilizing hidden members
The hidden members are a subset of priority 0 members because they have priority that is
equal to 0. These kind of members hold the same dataset as primary, but this will be invis-
ible to all the clients. Accordingly, hidden members won't receive any read/write opera-
tions, and as a result, they won't receive any traffic except normal replication and the
syncing process between
primary
node. In contrast, hidden members can vote in an
election.
Because hidden members will not receive any traffic, the main usage of the hidden mem-
ber can be for dedicated tasks such as reporting, backup, or disaster recovery server. The
following diagram shows you how to utilize hidden members:
