IO - Throughput / Data Transfer Rate (DTR) / Bit Rate

> I/O - (Input/Output|Read/Write) - Data Access

1 - About

Performance - (Throughput|Bandwidth|Transfer rate) in storage device.

Throughput or data transfer rate (DTR) is :

  • the speed at which data can be transmitted between devices. ie the rate at which information can be read from or written to the storage device.
  • or the amount of data processed in a given amount of time

This is the principal performance characteristic of a storage device.

In computer data storage, throughput is usually expressed in terms of megabytes per second or MB/s, though bit rate may also be used.

As with latency, read rate and write rate may need to be differentiated.

Also accessing media sequentially, as opposed to randomly, typically yields maximum throughput.

The available throughput is distributed among the concurrent users.

The two major techniques for throughput computing are:

To calculate a maximum throughput (Megabytes per second) of a storage device, you have to set a workload with:

  • a Transfer Request Size to 64K
  • a Percent Read/Write Distribution to 100% Read,
  • and the Percent Random/Sequential Distribution to 100% Sequential.

To calculate a maximum I/O rate (I/O operations per second) of a storage device, you have to set a workload with:

  • a Transfer Request Size to 512 bytes (equivalent of one sector/block)
  • the Percent Read/Write Distribution to 100% Read,
  • and the Percent Random/Sequential Distribution to 100% Sequential.

If you rely on storage shared with other applications then the throughput performance is not guaranteed and you will likely see inconsistent response times for your operations.

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3 - Dd

A disk write throughput test that uses “dd if=/dev/urandom” is a CPU test. Write that to /dev/null and see what you observe.

Linux - dd Utility (Dataset definition) - (Throughput test validation)

4 - Vizualization

5 - Unit

6 - Device

Bit rate by device:

io/throughput.txt · Last modified: 2019/01/03 15:21 by gerardnico