The test-reliability command writes one or more patterns to the drive, then reads back and verifies the data, all in the most efficient multi-threaded way.

If you suspect a drive problem, test-reliability is a good way to check it out. However, large drives can take a day or two to test thoroughly with multiple patterns, so you’ll need patience.

Running DiskTester test-reliability

Using DiskTester.app, choose Test Reliability. Suitable defaults are chosen. You can exercise more control using the command line.

DiskTester test-reliability

Command line usage

The command line allows greater control. Please use disktester help read-files for details on the available options. In general, there is little reason to use the command line.

    [--iterations|-i <count>]                               "1"
    [--xfer|-x <size[K|M|G|T]>]                             "4M"
    [--test-size|-t <size[K|M|G|T]|max>]                    "max"
    [--pattern|-p <0|1|01|10|randomblock|all|<any>>]        "all"


Various command line possibilities.

To read all files on volume Scratch 10 times:

disktester test-reliability --xfer 8M BadBoy
disktester test-reliability --pattern randomblock BadBoy
disktester test-reliability --pattern 0 BadBoy
disktester test-reliability --pattern 1 BadBoy
disktester test-reliability --pattern 0xDEADBEEF BadBoy
disktester test-reliability --pattern all BadBoy

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