stressdrive is a macOS and Linux command-line tool meant to verify correct operation of a drive. It does so by filling a drive up with random data and ensuring all the data can be correctly read back.
It was written to verify correct operation of de-duping SSDs, but it can be used with normal HDDs or any rewritable block storage device.
stressdrive will overwrite, without warning, all data on the given drive. Be sure to double-check the drive you're aiming it at (
diskutil list or Disk Utility.app > Select Drive > Info > Disk Identifier).
sudo ./stressdrive /dev/rdiskN
Run Only Against Entire, Unmounted, Physical Devices
stressdrive should always be run against entire unmounted physical devices.
Practically: your device path should always be in the form of
/dev/rdiskXsX). stressdrive's results can only be trusted if it was allowed to fill the entire device to the device's advertised information-theoretic maximum.
Imagine pointing stressdrive at just a logical partition. If the drive failed during the test it's possible to get back a clean read of the random data just written, while a block outside the device's partition is no longer correct. That would not be an accurate test result.
Here's stressdrive running against a 2 GB USB Flash drive:
$ sudo ./stressdrive /dev/rdisk999 Password: disk block size: 512 disk block count: 3948424 buffer size: 8388608 succesfully created no idle assertion writing random data to /dev/rdisk999 writing 100.0% (3948424 of 3948424) 00:03:54 6519594c7bf64d5e4e087cfbc5ba6324d25e8c0d <= SHA-1 of written data verifying written data reading 100.0% (3948424 of 3948424) 00:01:24 6519594c7bf64d5e4e087cfbc5ba6324d25e8c0d <= SHA-1 of read data SUCCESS succesfully released no idle assertion
First, you'll need OpenSSL, which you should install via homebrew:
brew install openssl
Then you can just:
Or compile it directly:
gcc stressdrive.c -o stressdrive -framework IOKit -framework CoreServices -I/usr/local/opt/openssl/include /usr/local/opt/openssl/lib/libcrypto.a
sudo apt-get install libssl-dev # You will need openssl headers gcc stressdrive.c -o stressdrive -std=c99 -lcrypto
"How is this better than Disk Utility's 'Zero Out Data'?"
Some SSD's de-duplicate stored blocks. For these "filling" it with zeros if actually just modifying one or two actual mapping blocks over and over again. It's not a real test of the SSD's hardware.
"How is this better than Disk Utility's '7-Pass Erase'?"
stressdrive only overwrites the drive with data once (so it's 7x faster) and then verifies all the data is correctly read back (which Disk Utility doesn't do at all).
Jens Ayton informs me 7-Pass Erase uses fixed patterns, so de-duping may be an issue there as well.
"Pshaw! I could do this with dd, /dev/random & shasum!"
Indeed you could. I prefer a minimal focused tool whose operation is fixed, its source simple+readable and offers good built-in progress reporting.
- [NEW] Display speed alongside progress. (Ivan Kuchin)
- [FIX] Statically link libcrypto. (rentzsch)
- [NEW] Linux support. (Ivan Kuchin)
- [NEW] Better progress display: elapsed time and ETA. (Ivan Kuchin)
- [NEW] Use AES 128 CBC with a random key and initialization vector as a much faster source of data sans fixed patterns. (Ivan Kuchin)
- [NEW] Don't allow the Mac to idle (sleep) while running. (Ivan Kuchin)
- [NEW] Print version alongside usage. (rentzsch)
- [CHANGE] Remove speed scaling in favor of a simpler and as fast fixed 8MB copy buffer. (Ivan Kuchin)
- [FIX] Possible overflow in speedscale. (Doug Russell)
- [FIX] Xcode project references Homebrew's OpenSSL in a non-version-specific way (so it doesn't break on every update). (rentzsch)
- [NEW] Speed scaling, which increases the copy buffer to the maximum that's still evenly divisible by the drive's capacity. (rentzsch)
- Initial release.