Tuning the load balancer for unequal servers
When all servers in the system are approximately equal, server loads should be optimal without manually tuning the
load balancer. However, when servers are unequal, the least powerful machine determines the overall throughput
unless you compensate by manually assigning a load balancing factor to each server. Since more powerful machines
can run more concurrent jobs and complete each job in less time, routing more traffic to them increases the overall
job capacity of the system.
The load balancer component is composed of three different Tomcat load balancing workers that separately manage
Lexmark Management Console (LMC) sessions, job submissions from e
‑
Task 2 and e
‑
Task 3 printers, and job submissions
from e
‑
Task printers. The adjustment shown here affects the e
‑
Task 2, e
‑
Task 3, and e
‑
Task load balancers, but not the
LMC load balancer. Each load balancer distributes jobs to servers in proportion to the load balancing factors assigned
to each server. For example, in a system with three servers with load balancing factors of 10,10, and 20, the first two
servers each receive 25% of jobs, and the third receives 50%.
The ideal job distribution depends on the hardware, network environment, and the solution being run. The optimal
proportions for load balancing factors can be found by running performance tests on each server. However, some
factors such as memory, number of processors, or CPU speed may suggest an initial value for the load balancing factor
to add more system capacity. Note, however, that performance improvements are not linear functions of numerical
improvements in hardware.
Perform the following steps on each server after initial values are determined for load balancing factors:
1
From the System Health dashboard, select the address of the server from the list in the Server Health section.
2
Adjust the Load Factor slider to the desired load balancing factor for the server.
Note:
These settings are not saved during an upgrade. If you upgrade your system, then you must repeat these
steps.
Assigning servers to only run LMC or process jobs
When using more than one server in a system, you can assign some servers to only run LMC and other servers to only
process jobs. When all servers are separated in this manner, it is usually adequate to assign only one server to run LMC.
When using a configuration 1
‑
N, X
‑
N, or X
‑
Y
‑
N system with the recommended hardware, it is recommend to do the
following:
•
Install the server component on the RAID 1 array where the operating system is installed on the load balancer
computer, and configure it to only run LMC.
•
Configure servers installed on dedicated computers to only process jobs.
1
Launch JK Status Manager from your Web browser using the URL
http://
loadbalancer
:9780/status/?
opt=454
, where
loadbalancer
is the computer where your load balancer is installed.
Server information and the worker status for each of the three load balancing workers appear. Each server in the
system is listed as a worker in each Balancer Members list.
2
For each server that should only process jobs, stop the associated worker on the adminloadbalancer load balancing
worker, which balances requests to LMC:
a
In the “Worker Status for adminloadbalancer” section, click
E
beside the server name.
b
For Activation, select the
Stopped
option.
c
Click
Update Worker
.
Monitoring and maintaining the system
65
