Estimating network bandwidth

Calculating OpenEdge Replication's effect on the network involves many different factors.

The presence of after-image data is the most significant determinant in how much bandwidth is needed. Exact data volume cannot be accurately calculated, as it depends on the type of transactions within the application and how much activity is going on against the database. However, it can be estimated if you know the average amount of after-image volume on your system. Use the following formula to help you calculate the values for capacity planning: 

AID x AIRM = AIDR
AIDR x AIRO = AIDRO
AIDRO X (PRD) = AIDROP
AID
The total size of all the after-image blocks.
AIRM
The value 1.5; the multiplier for additional after-image notes due to OpenEdge Replication.
AIDR
The number of after-image blocks with OpenEdge Replication.
AIRO
The value 1.1; the multiplier for OpenEdge Replication overhead.
AIDROP
The number of after-image blocks with OpenEdge Replication and overhead.
(PRD)

The period of time, as follows:

  • 1, if samples are 60 minutes and you want per-hour values
  • 1/60, if samples are 60 minutes and you want per-minute values
  • 24, if samples are 1 hour and you want per-day values
  • 60, if samples are 1 minute and you want per-hour values
  • 1/24, if samples are 24 hours and you want per-hour values
  • 1/1440 (which is 24 * 60), if samples are 24 hours and you want per-minute values

Example

  • Consider the following example, where:
    • AID is 89MB.
    • Sample length is 60 minutes.
    • PRD is 1.
    89MB x 1.5 = 133.5MB
133.5MB x 1.1 = 146.85MB
146.85MB x 1 = 146.85MB

    In this case, this customer would send approximately 146.85 megabytes of data to the target database per hour.

  • In the example that follows:
    • AID is 360 MB.
    • Sample length is 24 hours.
    • PRD is /1440.
    360MB x 1.5 = 540MB (566, 231, 040 bytes)
5540MB X 1.1 = 594MB (622, 854, 144 bytes)
594MB/1440 = 422 KB (432, 537)

    This customer would send approximately 422 kilobytes of data to the target database per minute.