What is auxiliary database redundancy?

Auxiliary database geographic redundancy

A geographically redundant, or geo-redundant, auxiliary database has one cluster of one, or three or more, auxiliary database stations in each NSP data center. The cluster that is designated the primary cluster processes transactions; the other cluster acts as a warm standby in the event of a primary cluster failure.

The primary cluster replicates the incremental database content changes on the standby cluster every 30 minutes. Because the primary database updates are not immediately replicated, some data loss may occur under failure or switchover conditions.

Auxilary database failovers

An auxiliary database failover is non-revertive; a manual switchover is required to restore the former cluster roles when the failed cluster returns to service; see How do I perform an auxiliary database switchover? for information.

NSP Analytics uses the primary auxiliary database as a data source. In the event of a primary auxiliary database cluster failure and resulting failover to the standby cluster, no operator intervention is required to restore Analytics functions, which automatically begin to use the new primary auxiliary database cluster.

Auxiliary database cluster switchover on the NSP UI

The System Health dashboard displays the primary and standby cluster roles for an auxiliary database cluster.

The dashboard also displays information such as the auxiliary database backup status, next backup, last backup, and copy cluster status.

From the dashboard, the NSP administrator can manually trigger a switchover between the primary and standby auxiliary database clusters.

After the first copy-cluster operation, the NSP administrator can trigger a switchover. When copy-cluster is copying, is unavailable, or fails, the Make active button for the standby cluster disappears on the dashboard.

If the auxiliary database backup is running, the switchover operation must not be performed until the backup is complete.

If a cluster node is down, the copy-cluster operation cannot be performed.

If a standby cluster node is down, the Make active button for the standby cluster disappears on the dashboard.