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For example, for disk and I/O capacity, each retrieve requires that the data is obtained from 
the archive (Tivoli Storage Manager, OAM, ASM, and cache). This data is on a disk or 
another storage device. The storage device retrieval rate is part of the total response time that 
is observed at the client, and both of them are affected by the following resources and system 
demand:
/SM590000Real memory: The data that is retrieved from disk must be stored in memory for it to be 
processed. Virtual memory allows large amounts of data to be swapped in and out of real 
memory, but it does not remove the need for real memory.
/SM590000Processing: Any data transformations that are performed on the Content Manager 
OnDemand server require available processing capability. If the capability is not available, 
the server waits until it becomes available. This wait lengthens the total response time of 
the client request.
/SM590000Concurrent retrievals: Each retrieval requires resources on the server. The higher the 
number of concurrent retrievals, the greater the amount of resources that are needed to 
complete the work in an acceptable amount of time.
/SM590000Network bandwidth: The retrieved data is sent to the clients over the Internet Protocol 
network. If the network bandwidth is not wide enough to satisfy all of the concurrent 
requests, the response time to the clients is slower and data is queued up in the server 
buffers, further slowing down the system.
13.3.3  Retrieval testing
The goal of retrieval testing is to verify that, under stressful system conditions, the maximum 
number of concurrent users can be served while at the same time the system meets the 
business requirements. The following process is a good general approach to retrieval testing 
of the system:
/SM590000Transaction type: Different types of transactions present different types of workloads on 
the system. For example, logon, document query, and document retrieval all use different 
components of the Content Manager OnDemand system. For each transaction type, 
measure the throughput and response time for a number of concurrent users that exceed 
the maximum predicted number. Tune and add resources to the system as needed until 
the system exceeds the service level agreement (SLA) requirements.
/SM590000Data types: The stored documents might be different sizes and data types (and might 
invoke preview exits). Multiple document retrieval tests must be run to verify the 
performance for the various types of stored documents.
/SM590000User workloads: The users that access the system might all exhibit the same usage 
patterns or might exhibit two or more usage patterns. The following process shows an 
example usage pattern:
a. Log on.
b. Wait five seconds.
c. Issue a document query with a maximum hit list size of 12 documents.
d. Wait five seconds.
e. Retrieve a 10 KB document.
f. Wait 40 seconds.
g. Retrieve a 20 KB document.
h. Wait 60 seconds.
i. Log off. 
For example, a total of 50 concurrent users might follow this pattern. Also, other patterns 
might run at the same time. So, the user workload test must model this behavior and it 
must also be able to meet the business requirements at peak loads.