How to measure disk throughput?

Question

I want to know how many bytes per second can I write to the disk and read from it.

How can I do that on linux machine?

Answer 1

Use a benchmark tool like bonnie(++). It's easy to install on about every distribution, and since it measures different aspects, you get quite a good picture how the system performs in a given situation.

If you just want to use basic tools, you could use dd:

For write speed:

dd if=/dev/zero of=outputfile bs=512 count=32M

(The product of bs and count should be at least twice your RAM size)

For read speed:

dd if=outputfile of=/dev/null

Remember that this is a very rough estimate and measures a situation that is unlikely to occur in normal operations.

Answer 2

Iozone, bonnie++, nmon (realtime) - they all work.

Answer 3

Josh Berkus gave a pretty detailed talk at pgCon 2009 on performance tuning; the first half or so is just dedicated to measuring disk I/O and solutions. It's big and long, but you only need to watch it once to get an idea of what sorts of things to think about.

Also take a look at the benchmarking video, which covers much of the same content.

Answer 4

I would just use hdparm to measure the read speeds of the drives:

hdparm -t /dev/sda

you can test read speeds on formatted drives with data on it but be careful with writing as if wrongly used can corrupt data.

Hope that helps, RayQUang

Answer 5

iometer has also been around for a while.