System Sizing Guidelines - Lexmark C792 Administrator's Manual

Installing Lexmark Document Distributor
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 an LDD system that uses a hardware load
balancer or GSS.

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 LDD 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
3
Determine the minimum number of servers:
(7500 jobs/hour) / (3000 jobs/hour) = 2.5
Rounding up, the system should include three servers to reliably handle the peak load for a solution with average
execution time below 30 seconds.
The single‑server throughput for a solution must be determined by the solution developer, though the following typical
throughputs on a server with the recommended hardware may help determine a rough estimate:
Solution processing load Functions used
Typical
•
Some image processing
•
Printing
Average single‑server throughput
6000–8000 jobs per hour
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