With this type of setup, you need additional computers, as well as a hardware load balancer or GSS. You also need to
manually configure these systems to be identical.
Note:
Printers that do not support eSF applications cannot be used with a Lexmark Intelligent Capture system that
uses a hardware load balancer or GSS.
When a hardware load balancer is used with multiple Lexmark Intelligent Capture systems, the hardware load balancer
must be configured as follows:
•
The X-Forwarded-For HTTP header must be inserted into incoming packets.
The packets going into the Lexmark Intelligent Capture systems from the HW LB should not appear to be from the
hardware load balancer of the packet headers so that device or clients groups and their settings will work properly.
•
Cookie-based session persistence must be disabled.
This is needed in case one of the Lexmark Intelligent Capture systems is down. If this is enabled, then LMC may not
work properly when one of the Lexmark Intelligent Capture systems is down.
•
The load balancing algorithm should be set to Round Robin.
Based on tests made on hardware balancing algorithms, Lexmark Intelligent Capture systems work better with
round robin than the other algorithms.
System sizing guidelines
There are two main factors for determining the number of servers required to process jobs efficiently:
•
Peak demand
—This is usually the deciding factor when the average execution time for a solution is under 30
seconds.
•
Concurrency
—This is usually the deciding factor when the average execution time for a solution is over 30 seconds.
Additionally, the database, when installed on the recommended hardware and connected using Gigabit Ethernet, can
process 200,000 logged messages per hour, which is approximately 40,000 jobs per hour when using a typical solution
(five logged messages per job). If this limit is reached, then it may be necessary to use multiple systems.
Peak demand
Use the following formulas to determine the number of servers necessary to handle peak loads for a particular solution:
(System
‑
wide hourly job rate)
= (system printer capacity) x (jobs per printer per day) / (length of business day)
(Peak demand)
= 2 x (system
‑
wide hourly job rate)
(Minimum number of servers)
= (peak demand) / (single
‑
server throughput for current solution)
Consider the following example:
•
Each server in your system can process 3000 jobs per hour using the solution.
•
There is capacity for 300 printers in your system.
•
Each printer in your system averages 100 jobs per day.
Perform the following calculations:
1
Determine the system
‑
wide hourly job rate:
(300 printers) x (100 daily jobs/printer) / (8 hours/day) =
3750 jobs/hour
2
Determine the peak demand:
2 x (3750 jobs/hour) =
7500 jobs/hour
Installing Lexmark Intelligent Capture
31
