This note is intended for clarification on how the bandwidth throttling works and to avoid misinterpreting output from network bandwidth monitoring utilities. The local server sends the data to the offsite replication server in 64 kByte packets, an optimal size for processing across the file system on various OS versions and for overall efficiency for transfering data on the whole. Just prior to sending each 64 kByte packet, the local server computes the transfer rateand pauses if required to attain the specified rate.

The 64 kByte data packet is transmitted by the local server at the network connection speed. The tranmitted bits cannot be slowed down to provide a constant rate. Hence, bandwidth monitoring graphs that are collecting data at a very high frequency could show a spike in the number of bits per second transferred that exceeds the throttle setting. However, the overall average between the spikes caused by each 64 kByte packet averages out the the throttle setting.

The total time it takes to transfer a file is consistent with the throttle setting. Also, taking the average across multiple "spikes" in a network monitoring graph's output will also show that the average between the transfers are occurring the specified rate.


Legacy Forum Name: Bandwidth throttling,
Legacy Posted By Username: PWong