About the Iperf tool

Article:HOWTO64300  |  Created: 2011-12-29  |  Updated: 2012-01-12  |  Article URL http://www.symantec.com/docs/HOWTO64300
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About the Iperf tool

The Iperf tool is a third party tool that can create TCP and UDP streams to measure the throughput of a network. Iperf has been accredited by many major US institutions and is commonly available pre-compiled for many operating systems in their package repositories or on freeware sites. However, Iperf is not linked with nor sponsored by Symantec, and as such any defects or bugs found with Iperf should be reported directly to the Iperf developers and not to Symantec technical support.

When dealing with network connections and Veritas Volume Replicator (VVR), you must consider the following points:

  • The rated speed of a piece of network hardware or connection is the theoretical maximum throughput that can be achieved in a burst in ideal conditions. As such, the real world maximum throughput that can be achieved is likely to be somewhat lower than the rated maximum throughput.

  • Network throughput is commonly measured in bits per second, such as Mbps (megabits per second) or Kbps (kilobits per second). These are an order of magnitude smaller than data storage sizes such as MB (megabytes) or KB (kilobytes). As such, a network card rated at 100 Mbps can only transfer a theoretical maximum of ~12.5 MB of data per second.

  • 1 Mbps equals 1000 Kbps and 1 Kbps equals 1000 bps, not 1024 bps. This is different than data storage sizes where 1 MB equals 1024 KB and 1 KB equals 1024 bytes.

  • The peak throughput achievable by VVR when replicating is likely to be somewhat lower than the maximum throughput found by network testing tools such as Iperf. This is due to the design of the VVR product making it particularly sensitive to network features such as dropped or reordered packets and packet fragmentation. VVR's use of the network is inherently more complex than the tests performed by simple network test tools.

See Using Iperf to diagnose network issues

See About Veritas Volume Replicator network configuration tuning


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