steps, then the document must traverse the network between the client application and the server six times. If the resource image is 50 KB and we have to process 10,000 images per 8-hour day, then we can calculate the network traffic approximately as follows: 50 KB * 10,000 images/day * 6 times on the network (8 hours * 3600 seconds/hour) = 100 KB / second = 800 Kb per second (average) Although the work process might take weeks to complete, in order to keep a steady workload (in this example, no build-up of work in the system), then the system needs to process the number of items equivalent to the number entering the system each day. This means, in our example where 10,000 items entering the system everyday, the system needs to process 10,000 items every day to avoid a backlog. The calculation above is only approximate, because additional header and trailer information is appended by the HTTP response, and neither the request nor calls to the Library Server are considered. This does not seem to be much load when minimum LAN speed is 10 Mb per second; however, the network is not installed specifically for this system. All estimates for the network traffic have to take account of existing network traffic and that the effective throughput of a 10 Mb LAN is really only about 6 Mb. Another factor that affects the calculation above is the difference between average and peak utilizations. Often, the end users’ work habits can mean that the majority of the work is done in certain highly productive time slots. Some users might get a late start each morning, by doing things other than “real” productive work, such as reading e-mail, getting coffee, conducting meetings, and doing other administrative tasks. Users might delay serious production work until mid-morning. This could present a peak system utilization demand during mid-morning. Lunch time can have an effect as some users go early and some go late. The workload declines around the lunch break. There might be another peak period in the afternoon after the late lunch. Finally, closing time also has an effect because some users go home early, and others stop using the system in preparation for closing up for the night or finishing other activities. This all means that peak load can be two or more times the average load. When considering network performance, batch processing and overnight processing must be included. Object replication and migration move large amount of data over the network. Typically these background tasks can be done at any time; they are best deferred to times when user activities are low. Prefetching items during the off hours in preparation for the next day’s processing is another
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Performance Tuning for Content Manager