Consultor Eletrônico

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GOAL:

How to determine the amount of AI file space required?

FIX:

To determine the amount of AI file space required, use the PROMON utility BI Log Activity Display to monitor the number of BI writes that occur during the activity period that you want to use after-imaging. The information that is written in the BI file closely matches what is written in the AI file. Typically 0.05% fewer bytes are written to an AI file than are written to the BI file. Therefore, the BI Bytes written statistic provides a close estimate of the space required for an AI file for the same activity period.
Measure the BI Bytes written statistic several times toward the end of the activity period that you are considering using after-imaging. If your workload varies from day to day or peaks during end-of-month processing, count the BI writes during a peak period to ensure that you allocate enough space to handle peak days. If the workload grows, make sure you increase the amount of space available for AI files. Always have extra disk space available for unanticipated growth of the AI file.
With OpenEdge 10, another way to calculate your AI file size is to use Before-Image Cluster Size from the PROMON utility BI Log Activity Display and the Checkpoints from the Activity Display. If you want your AI file to hold all the changes made over a two hour period, determine how many checkpoints occurred during a 2 hour time period of peak activity. The number of checkpoints times the BI cluster size will equal the minimum size your should make your AI extents to capture the changes. For example, if you have 4 checkpoints in 2 hours, and each cluster is 0.5MB, then you need your AI files to be at least 2.0MB to record 2 hours of activity. Once you have sized your after-image areas, you need to manage them so that there is always space available to write in an extent.