How to handle multiple disks simultaneously with Disk Utility

DiskUtilityIconXRegardless of the number of storage devices you have attached or built into your Mac, you will likely use Disk Utility for formatting them when necessary, to partition and resize them for various purposes, and otherwise managing them. However, one limitation you might find when using Disk Utility is that it will only act on one drive or volume at a time.

For the most part this is not much of a problem, since operations like a quick format or partitioning of a device can take only a few moments; however, there are times when longer operations on one device can have you waiting around to perform operations on other devices. For instance, if you have a number of drives that you want to securely format or zero-out, it may take hours to format each one. You might also be in the middle of performing a drive wipe, and wish to test another drive you have on hand.

Even though Disk Utility will only run one such operation at a time, there are a few tricks you can use to get around this limitation.

1. Select multiple devices for verification and repair

When performing First Aid routines such as verification or repair on a device, you generally do so on one selected device in Disk Utility’s sidebar; however, you can quickly do this on multiple devices by holding the Command key and then clicking each to add them to a selection. You can then run your verification and repair on the selection, and Disk Utility cycle through each selected disk to perform these actions.

Disk Utility in OS X

With multiple drives selected in Disk Utility, clicking Verify Disk will check them for errors. You can use the Repair routine for this as well, provided you do not have the boot drive in your selection.

2. Launch multiple instances (or windows) of Disk Utility

For operations where Disk Utility cannot act on a selection of disks, like formatting disks, you can still perform multiple instances of these operations at a time. In Disk Utility, you can press Command-N to open a new window, but another approach you can take is to launch multiple instances of the program. By default, OS X will only open one instance of an application, so double-clicking a program that is already open will switch to it, instead of launching a new process; however, you can run a second instance of a program, if needed.

To do this for Disk Utility, open the Terminal and run the following command for as many separate instances of Disk Utility that you would like to launch:

open -n -a "Disk Utility"

With these instances open (either as a new window, or as separate processes), you can now use one to start a long format process on one of your disks, and use another for a similar process on another disk.

Multiple instances of Disk Utility launched

Running the “open” command multiple times will launch multiple instances of Disk Utility, which like pressing Command-N to open a new Disk Utility window, will allow you to select different drives in each on which to perform various actions.

Note that multiple instances of programs should only be done on non document-based programs, that is, programs that do not support files you can save and open in multiple windows (e.g., TextEdit, or Pages). Having multiple instances of the program open will affect services like Apple’s Autosave and Resume, and may overwrite or delete unsaved work you have open in these programs.

3. Use the “diskutil” terminal command

Launching separate Disk Utility processes is similar to opening different Terminal windows and using the “diskutil” command in each to perform actions on separate disks. The specific uses of this command will require you be a little familiar with the Terminal; however, as a general principal you can run the following command to get a list of your disk device IDs, which will be labeled something like disk0, disk1, disk2, etc., or individual partitions by their “slice” identifier, such as disk0s2, or disk1s1, etc.:

diskutil list

Following this, you can perform your desired actions on your drives or slices in separate Terminal windows, and this will have the “diskutil” command operate on your drives all at once, as opposed to having to perform them sequentially in one Terminal window. Note that in most cases, after supplying the diskutil command’s various arguments and options, the last argument is to supply your drive device. You can do this by typing its device identifier, but can also do this by specifying the full path to the root of the device. Since the OS X Terminal supports drag-and-drop for entering file paths, an easy way to run various commands on different drive devices is the following:

  1. Open a new Terminal window
  2. Type in your diskutil command and arguments (e.g., “diskutil zeroDisk”) followed by a single space.
  3. Drag your desired disk from the Finder to the Terminal window to enter its full path as the last command argument.
  4. Press Enter to run the command.

As this command runs its course, you can repeat this procedure to quickly run another instance of diskutil on another volume and get another formatting process going. As with launching multiple instances of Disk Utility, this can be a quick way to attach a series of devices and format or otherwise manipulate them.

16 thoughts on “How to handle multiple disks simultaneously with Disk Utility

  1. Me In LA

    Well, running in 10.10.x, I need to use this to work:
    open -n -a /Applications/Utilities/Disk\\ Utility

    1. Topher Kessler Post author

      The -a flag specifies the application by name. If this is not working, then you need to reset your Mac’s launch services so they will be updated with the proper applications and application capabilities that you have installed on your Mac. To do this, in the Terminal run the following command (both lines at the same time):

      chServices.framework/Versions/A/Support/lsregister -kill -seed

      1. Strod

        “Disk Utility” and ‘Disk Utility’ both work. Notice that both are the simple, straight double and single quotes.
        The problem is that when Topher copied the command, the double quotes were converted into the fancy curved quotes that have ‘open’ and ‘close’ versions: “Disk Utility” (look closely and you will see the difference).
        Many programs convert the straight quotes to the curvy ones (also single ones: ‘ and ’), a feature called “smart quotes”, because the curvy ones look better. But the command line only likes the simple ones, so authors like Topher should be on the lookout.

        1. Strod

          Ha! Now I see that this freaking forum also converts quotes, and all the straight ones I carefully typed were converted into the curvy type. Hopefully you get my point regardless.

          1. Strod

            Let’s see if this works:
            open -n -a "Disk Utility"

            If it did work, some of you may like to know that I produced it by typing:
            [code]open -n -a “Disk Utility”[/code]
            with angle brackets (less than and greater than) instead of square ones.

          2. Topher Kessler Post author

            I fixed the issue. For some reason the quotes were turned into smart quotes, which was cause for some confusion, especially when copied and pasted from here.

  2. cortig

    With a simple Command-N in Disk Utility, you can open a new window, select different disks to do whatever else you want to do. No need to launch multiple instances of the app itself.

    1. Topher Kessler Post author

      Yes, I am somewhat math-oriented, and love the versatility of LaTeX. I’m a fan of all open-source and free math and analytical software: Maxima, Octave, Grapher, etc. I haven’t found a favorite equation editor yet, but I’m always on the lookout for a good one, similar to how in Grapher you can start typing out the equation and it will assemble it live for you. I’ve got MathType, but even this from my uses requires you click objects in toolbars and menus to enter a fraction, or similar. I’d like something where I can select a component of an equation, then type “/” and it will know I’m intending the selection to be in the numerator of the fraction (or likewise with brackets, braces, etc.), and typeset it accordingly. Grapher does this great, but I’d like something that’s multi-lined and implemented in a text editor so I can just start typing as I normally would and have it convert the equations on the fly.

      1. Strod

        Have you tried LyX? More than just an equation editor it’s a full-fledged “What You See Is What You Mean” word-processor… more like a front-end for writing full documents in LaTeX. You can think of it as a free, open-source Scientific Workplace (though I never used S.W., so I may be wrong).

        Unfortunately LyX comes from the Linux world which means that on OS X the interface feels a little clunky, a little out of place, and it doesn’t play as nicely with others as regular Cocoa apps.

        So, it won’t quite solve your problem, as you apparently want integration with non-LaTeX-based software. But it does, for example, build mathematical equations as you type them in LaTeX code, while still giving you toolbars and menus for when you don’t know the LaTeX (and by using them it shows you the code/commands, so you learn).

        BTW, you may also want to take a look at BibDesk. It’s a fantastic bibliography manager much like Zotero or Mendeley (and thus so much better than EndNote), also free and open-source. One big advantage is that its native format is BibTeX, and therefore it plays very nicely with all LaTeX-based software.

        I used LyX and BibDesk to write all my theses (BS’s in Math and Electrical Engineering, MS and PhD in Biomedical Engineering), and I’m a far less bitter person now because I didn’t use Word for that!   ;o)

        Unfortunately now I work in a Word-only environment, so I have been forced to leave all those fantastic tools aside. It’s sad because even though I feel that Word is a better tool for the general public, academic writing is one of the instances where it is simply the wrong tool.

  3. MaX

    Great article. Although
    open -n -a “Disk Utility”
    does not work on Mac OS X 10.11.6 (15G1004) El Capitan.

    You can open two Disk Utility Windows, but then only one executes erase (select volume, not disk to show Security Options in El Capitan). So, you cannot erase more than one disk at once.

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