There are two ways of tacking the question, proactive and reactive.
One can get a rough estimate the amount of data captured by SharePlex. This is one measure of the bandwidth needed since whatever is captured by the SharePlex’ Capture process will be sent to the target. However, though the amount of data captured by Shareplex is proportional to the amount of redo generated on source database. The database changes constitute approximately 33% of the redo logs generated. Since Shareplex replicates changes to the source database, and since not all but a subset of tables are replicated, a conservative estimate can be derived. In addition, slightly more bandwidth may be needed for tables involved in CDC replication as more data is sent to target due to target tables having extra columns.
Once the bandwidth requirement is estimated and the replication established, it is possible to find out how much data was sent across from Export on source to Import on target over the longer time horizon. The “show export detail” output has the following section that summarizes the average transmission rate in kb/sec (termed here as “Transmission rate”) and also displays the high watermark of the transmission rate (termed here as “Highest transmission rate”) since the time the replication begin under the most recent activation:
Transmission rate : 5 Kb/sec
Highest transmission rate : 10 Kb/sec Mon Aug 18 14:45:49 2014
If the highest transmission rate differs vastly from the average, then it could mean there are periods of busy activity, something that is normal in database.
The reactive approach will give out more accurate statistics though the proactive approach serves as a good starting point and one can later narrow it down by the “show export detail” stats.
Here are some more interesting facts:
The ability of Shareplex Export process to compress the data when it is sent by it to target can help you reduce this bandwidth requirement. The feature is available in Shareplex 8.6.3 and up. You need to set the parameter SP_XPT_ENABLE_COMPRESSION to 1. Here is the description of the parameter:
This parameter controls the compression of data across TCP/IP.
You can enable compression to reduce the amount of data that SharePlex sends across the network. SharePlex uses LZIP lossless compression. Enabling compression on the source SharePlex instance automatically enables compression to all targets of the source SharePlex instance.
By default compression is disabled. You can enable compression by itself or in conjunction with encryption.
For more information about encryption, see Encrypt data across the network in the SharePlex
Default: 0 (disabled)
Range of valid values: 0 or 1 (enabled)
Takes effect: After restarting Export
Slightly more bandwidth may be needed for tables involved in CDC replication as more data is sent to target due to target tables having extra columns.