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Stress test your disks / memory cards / USB sticks before trusting your valuable data to them
Go Shell
branch: master


This is a program designed to stress test your disks and find failures in them.

Use it to soak test your new disks / memory cards / USB sticks before trusting your valuable data to it.

Use it to soak test your new PC hardware also for the same reason.

Note that it turns out to be quite a sensitive memory tester too so errors can sometimes be caused by bad RAM in your computer rather than disk errors.


StressDisk is a Go program and comes as a single binary file.

Download the relevant binary from

Or alternatively if you have Go installed use

go get

and this will build the binary in $GOPATH/bin. You can then modify the source and submit patches.


Use stressdisk -h to see all the options.

Disk soak testing utility

Automatic usage:
  stressdisk run directory            - auto fill the directory up and soak test it
  stressdisk clean directory          - delete the check files from the directory

Manual usage:
  stressdisk help                       - this help
  stressdisk [ -s size ] write filename - write a check file
  stressdisk read filename              - read the check file back
  stressdisk reads filename             - ... repeatedly for duration set
  stressdisk check filename1 filename2  - compare two check files
  stressdisk checks filename1 filename2 - ... repeatedly for duration set

Full options:
  -cpuprofile="": write cpu profile to file
  -duration=24h0m0s: Duration to run test
  -logfile="stressdisk.log": File to write log to set to empty to ignore
  -s=1000000000: Size of the file to write
  -stats=1m0s: Interval to print stats


Install your new media in your computer and format it (make a filesystem on it).

Open a terminal (or cmd prompt if running Windows)

To check the disk

Linux: ./stressdisk run /media/nameofnewdisk
Windows: stressdisk.exe run F:

Let run for 24 hours. Note whether any errors were reported. Then use

Linux: ./stressdisk clean /media/nameofnewdisk
Windows: stressdisk.exe clean F:

If you find errors, then you can use the read / reads / check / checks sub-commands to investigate further.

2012/09/20 22:23:20 Exiting after running for > 30s
2012/09/20 22:23:20 
Bytes read:         20778 MByte ( 692.59 MByte/s)
Bytes written:          0 MByte (   0.00 MByte/s)
Errors:                 0
Elapsed time:  30.00033s

2012/09/20 22:23:20 PASSED with no errors

Stress disk can be interrupted after it has written its check files and it will continue from where it left off.

The default running time for stressdisk is 24h which is a sensible minimum. However if you want to run it for longer then use -duration 48h for instance.

How it works

Stressdisk fills up your disk with identical large files (1 GB by default) full of random data. It then randomly chooses a pair of these and reads them back checking they are the same.

This causes the disk head to seek backwards and forwards across the disk surface very quickly which is the worst possible access pattern for disk drives and flushes out errors.

It seems to work equally well for non-rotating media.

The access patterns are designed so that your computer won't cache the data being read off the disk so your computer will be forced to read it off the disk.

Stressdisk uses OS specific commands to make sure the data isn't cached in RAM so that you won't just be testing your computer RAM.


I wrote the first version of stressdisk in about 1995 after discovering that the CD I had just written at great expense had bit errors in it. I discovered that my very expensive SCSI disk was returning occasional errors.

It has been used over the years to soak test 1000s of disks, memory cards, usb sticks and found many with errors. It has also found quite a few memory errors (bad RAM).

The original stressdisk was written in C with a perl wrapper but it was rather awkward to use because of that, so I re-wrote it in Go in 2012 as an exercise in learning Go and so that I could distribute it in an easy to run single executable format.


This is free software under the terms of MIT the license (check the COPYING file included in this package).

Contact and support

The project website is at:

There you can file bug reports, ask for help or contribute patches.



  • Yves Junqueira for code review and helpful suggestions
  • dcabro for reporting the windows empty partition issue
  • Your name goes here!
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