Mac OS X: Read Linux ext3 / ext4 External USB Hard Disk Partition

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How do I read (mount and access files) ext3 / ext4 external hard disk partition under Mac OS X?

Apple Mac OS X cannot directly mount and use ext3 and/or ext4 file systems. In other words, you need to use 3rd party driver or application to access ext3 / ext4 file systems. Another option is to use Oracle VM VirtualBox application which is an x86 virtualization software package for OS X. You can use any guest os like Debian, Ubuntu or Fedora Linux to access ext3 / ext4 file systems.


Configure VirtualBox To Access External USB Device

Open the VirtualBox app but do not start Linux guest operating systems. Do not attach external USB hard disk. First, select guest operating systems and click on settings (Machine > Settings).

Fig.01: Linux Virtualbox Guest Settings
Fig.01: Linux Virtualbox Guest Settings

Click on Ports tab. Do not click on add button which shows all USB devices as follows:
Fig.02: List of all detected USB devices
Fig.02: List of all detected USB devices

You need to add a new usb filter so that Virtualbox grabs external hard disk before Apple OS X:

Fig.03: Adding a new USB filter
Fig.03: Adding a new USB filter

The new empty string (new filter 1) will match to any attached USB disk. Now, start your Linux guest and wait till you see Linux console or GUI login window. Connect your USB hard disk to Mac OS X (usb device detected as /dev/sda):
Fig.04: Linux VM detected USB hard disk / USB pen
Fig.04: Linux VM detected USB hard disk / USB pen

Login to Linux guest using ssh or console. You can see your external hard disk details using any one of the following commands under Linux:
tail -f /var/log/messages
fdisk -l
You can mount it as follows:
mkdir /media/usb
mount /dev/sdd1 /media/usb

Replace /dev/sdd1 with actual device name.

How Do I Copy Files To Apple OS X?

You can install samba on Linux and share file with Apple OS X. Another option is to use rsync or scp / sftp client from Apple OS X:
rsync -av user@debian.guest:/media/usb/datadir1/ ~/Desktops/datadir1/
scp user@debian.guest:/media/usb/data/sales.dat /path/to/dest


Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

13 comment

    1. MacFuse is good but will not read EXT4 partition , in which case the awesome guide above is the only solution.
      thank you!

  1. Awesome tip! I can use this.

    MacFuse makes your entire system very unstable. It gives many kernel panics. Eek! YMMV.

  2. It’s perfectly stable, at least under Snow Leopard. But I can’t find any module yet for ext4.

  3. What about mounting Ext3/4 volumes under PowerPC OS X (the “PowerPC” part is very important)? I suppose “an x86 virtualization software package” wouldn’t help there.

  4. Thank you for this great guide! After I read and followed your instructions step by step it worked like a charm.

  5. Thanks for doing the heavy lifting here! My only comment is that I had to install the Extension pack for VirtualBox 4.2.6, but that was a non-issue. My Ubuntu VM auto-mounted the drive. Very cool.

  6. One thing I find somewhat disconcerting is that a year later, using ANOTHER operating system is still the only real solution. I can understand windoze not having an easy path to ext3/4, but osx? It just doesn’t seem reasonable. I guess I shouldn’t complain — all I really use my mbp for is the host for my virtualbox guests, which actually do all of the heavy lifting. I love my mbp — I just wish apple loved it as much as the users do.

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