When creating a redundant environment, it's important to understand the terminology and options. Clustering, as enabled by Lotus
®, is the ability to replicate Lotus Domino
databases across multiple servers. This is typically utilized with the Lotus Domino
mail databases. Lotus Notes
® Traveler servers can take advantage of mail database clustering. However, Lotus Notes
Traveler itself cannot take advantage of Lotus Domino
database clustering due to the fact that much of the Lotus Notes
Traveler server data is not stored in a Lotus Domino
High Availability (HA) is a general term that implies a high percentage of system availability ensured by a redundant infrastructure. Lotus Domino
Clustering is how Lotus Domino
can provide high availability of mail access. It is now possible to set up multiple Lotus Notes
Traveler servers using a shared enterprise database. If a server in the pool goes offline, devices can connect to other servers in the pool without loss of data. This pool of Lotus Notes
Traveler servers in conjunction with mail clustering provides highly available mobile mail access. Although clustering and high availability can be considered synonymous, the term High Availability is used with Lotus Notes
Traveler to avoid confusing the implementation with that of Domino
clustering. Disaster recovery (DR) typically refers to enabling a backup environment that will only be utilized in the event of a failure of the primary service. A disaster recovery environment may or may not require manual intervention. Lotus Notes
Traveler, even as a stand alone server, can be setup for disaster recovery.
Which degree of redundancy is implemented will depend on both your availability requirements as well as the infrastructure investment desired.
High Availability (HA)
Lotus NotesParent topic: Planning for installation and configuration
Traveler servers can be configured to use a shared enterprise database. This configuration is referred to as a High Availability (HA) pool.
There are several methodologies to employ with Lotus Notes
Traveler to recover from a server crash or failure.
Domino mail clustering
The Lotus Notes
Traveler service detects mail file replicas by reading the replica entries in the Lotus Domino
cluster directory database (cldbdir.nsf
) on the mail server of the user. This database must grant at least reader access to the Lotus Notes
Traveler server or servers (in an HA pool). Otherwise, the Lotus Notes
Traveler server never fails over the connection to an alternate server for mobile users if their primary Domino
mail server is down.