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run-sequential-suite

Therun-sequential-suite command measures read and write performance across a range of transfer sizes.

Before testing:

Exclude the volume from Spotlight search and Time Machine backup prior to testing!

Running DiskTester run-sequential-suite

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

The summary output can be graphed using the supplied spreadsheet (see below). Copy and paste the summary output into the spreadsheet template.

img
DiskTester run-sequential-suite

Graphing the results

Graph the results using the supplied spreadsheet.

Graphing the results yields an immediate feel for small vs large transfer size performance.

Remember, testing can be done on a volume which is a single disk partition, a RAID, etc.

The graph below is for the OWC Mercury Extreme SSD. These results are exceptional for a single drive of any kind.

img
Click to view larger size

Command line usage

The command line allows greater control. Please use disktester help run-sequential-suite for details on the available options. 

run-sequential-suite
    [--iterations|-i <count>]                   "1"
    [--starting-xfer|-s <size[K|M|G|T]>]        "32K"
    [--ending-xfer|-e <size[K|M|G|T]>]          "256M"
    [--test-size|-t <size[K|M|G|T]|max>]        "2G"
    [--test-area|-a <start|middle|end|xx%>]     "start"
    <volume-name>

Examples

Various command line possibilities. The iteratations and test size can be used to reduce test time, so long as results are consistent.

disktester run-sequential-suite Scratch
disktester run-sequential-suite --iterations 3 Scratch

To fill a drive with a random stream (torture test for some solid state drives):

disktester run-sequential-suite --iterations 5 --test-size 4G Scratch

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