Data Volume (Queue Disk Space Requirements)

The most significant components in estimating the amount of resources required by the replication system are the volume of the data being replicated and the rate at which it is being updated.

• Overview of Disk Queue Size Calculation
  A graphical representation that illustrates the sequence and flow of calculating data volume and queue disk usage.
• Change Rate (Number of Messages)
  The change rate is the maximum number of modifications (inserts, deletes, and updates) made to the table per time period. Change rate varies from table to table.
• Change Volume (Number of Bytes)
  The change volume is the amount of data changes in the table per time period. This amount varies; it is a function of the change rate and data size for each table.
• Calculating Table Volume
  The volume of data being replicated is the size of each message times the number of messages replicated per second.
• Overall Queue Disk Usage
  Calculate the overall disk space.
• Additional Considerations
  When planning your replication system, take the described considerations into account.
• Example Queue Usage Calculations
  A series of sample calculations using the formulas for calculating the disk queue size.
• Message Size Example Calculations
  Sample calculations using the formulas for message sizes.
• Change Rate
  The change rate is the maximum number of data modifications performed on a table per time period. The change rate differs for every table in your replication system.
• Table Volume Example Calculations
  Calculates the table volumes for tables T1, T2, and T3.
• Inbound Database Volume
  An example that calculates the inbound database volume.
• Inbound Queue Size Example Calculation
  An example that calculates the inbound queue size.