Disk Input/Output Performance Test with Linux¶

Looking aroung on Internet I found really good tools for testing read and write speed of storage devices on Linux and I am going to leave these commands here for future use.

Note

The dd command as the reference manual say is a tool for copy a file and we are going to use it for doing the test.

Write Speed¶

sync ensures that the filesystem cache is flushed to have more realistic data.

if=INPUTFILE: read bytes from this file
of=OUTPUTFILE: write bytes to this file
bs=BYTES: the number of bytes that are written and read at a time
count=BLOCKS: the number of time the reading and writing is repeated

$ sync; dd if=/dev/zero of=~/test.tmp bs=500K count=1024

256+0 records in
256+0 records out
131072000 bytes (131 MB) copied, 4.05327 s, 32.3 MB/s

Read Speed¶

With the first command the memory is flushed in order to have more reliable test. For the reading test dd copy the file in the special filesystem object /dev/null.

$ sync; echo 3 | sudo tee /proc/sys/vm/drop_caches
$ sync; time dd if=~/test.tmp of=/dev/null bs=500K count=1024

256+0 records in
256+0 records out
131072000 bytes (131 MB) copied, 6.789 s, 19.3 MB/s