Lexmark C792 - Reliability, Scalability, and Disaster Recovery

Solution
*.solution file
-Scripts
-Policy
Welcome Screen Layout
Device Settings
Solution Settings
Local
Global
-eSF
-3rd party jar files
-Status Page
LDD
Clients Group(s)
Device Group(s)
Load
Balancer
Data Base
Server(s)
LDD
Adminstration
LMC
Reliability, scalability, and disaster recovery
The load balancer, database, and server components may be installed together on one computer or separately on
individual computers, depending on the demands placed on the system. However, a one‑computer setup is subject to
downtime if that computer fails, and the server load will be fairly limited. Ideally, a system should have at least two
server computers, connected to separate database and load balancer computers.
LDD is scalable to support a large number of clients, submitting jobs to as many servers as required to handle the load.
The load balancer selects a server for each received job to distribute the total load and maintain system performance.
Using multiple servers also increases system reliability. If one server fails, then the load balancer will direct jobs to the
other servers until the failed server is back online.
LDD uses a Tomcat Connector to manage load balancing in the system. The default balancing method is session, which
estimates the number of sessions open by counting requests to the system that do not have a session cookie. The
session count is decayed by dividing in half, once per minute by default. The server with the lowest number of estimated
sessions is selected to process the request.
To further increase reliability by keeping the system online in the event of a failing load balancer or database, the load
balancer and database can each be paired in a failover cluster using a Microsoft Cluster Server (MSCS).
Lexmark Document Distributor overview 10