Ext2/3 Partitions - Mounting them on the Desktop

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Revision as of 19:59, 16 January 2007 by Davy gravy (Talk | contribs) (Before connecting)

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  • Data Recovery and Access: If you need GUI-based access to the contents of a hard drive, or if you need to mount an ext2/3 hard drive on a computer running Windows or OS X, this page may have an answer for you. The process outlined here is useful for someone rescuing data from a backup USB hard drive, or from a data partition in a Linkstation.
  • Filesizes in the terabyte range: Why would you want ext2/3 format anyway? Well Windows formats (FAT, FAT32, NTFS) have some serious limitations to them, namely filesize. For FAT the filesize limit is 2GB, and for FAT32 or VFAT is it 4GB. OS X doesn't have these limitations for its HFS+, but it is a proprietary format and is not readable to many computer systems. Therefore, ext2/3 is a viable alternative. With drivers, it is readable by nearly all OS's, and it has a filesize limit that runs in the terabytes.
  • Not being locked out: Perhaps the biggest reason for many FreeLink users is that Buffalo has for years used a proprietary ext2-like format for USB hard drives attached to the Linkstation. This format has a large filesize limit, but it does not mount under Linux, Windows or OS X. Moving to Freelink gives us the opportunity to unplug that USB drive and mount it directly to ones desktop, using the methods shown here.


  • a USB storage device (flash, IDE or SATA) or hard drive formatted in ext2 or ext3
  • a computer running
    • OS X (10.3-10.4.x are currently supported),
    • Windows or
    • Linux/Unix
  • for OS X: ext2fsx driver at SourceForge.net
  • for Windows: explore2fs or Ext2 Installable File System For Windows
  • for Linux: Any common desktop distribution (including a bootable or Live CD from Ubuntu or Knoppix) already comes with ext2/ext3 support
  • for Unix: Ask the vendor for an ext2/ext3 file system implementation
  • for any partition that was formatted by original/stock Linkstation firmware, you may need first to use Fix ext2 magic to make it readable by machines other than a Linkstation


Before connecting

Connecting and Determining disk info





Before connecting

Make sure that you have ext2fsx installed. Read its documentation (in the ReadMe.rtf) before going further. Be aware that if it detects a filesystem that isn't clean, it will run fsck_ext on it automatically.

If you have the disk/partition mounted, make sure that you unmount it cleanly from current mount point. Double check that it is unmounted by using

df -Th

in Linux or whatever the analogous command is in your operating system.

NOTE: As of version 1.4d, journaling is not supported in extfsx. Unjournaled writes to a journaled device can cause irreversible damage and unrecoverable data loss. For non-journaled drives, write access sometimes works, but has cause kernel panics for some users. Be careful to mount it read-only if you have valuable data on it that you don't want to lose.

Mounting & Unmounting

  • Connect your drive to your computer, either by USB or via an IDE/SATA cable.

via the GUI

  • The GUI interface provided through the Preferences Pane in OS X usually works out of the box, provided the volume you try to mount is clean. As of version 1.4d4, write access to nonjournaled volumes works, but some of us have experienced kernel panics when writing. To avoid problems, it may be safer to:
    • Open System Preferences
    • Select ExtFSManager
    • Select the ext2/3 device, and then the carrot/triangle just to its left, to view the volume you want to mount
    • Select the volume and then the Option button. Check the Mount Read-Only
    • Unmount it and then mount it again. Subsequent mounts should remember the options, but might not.
  • To unmount, use the normal Eject function in the Finder.

via Command Line

If the GUI doesn't work for you then the command line method might still get you connected. You must log in as administrator, make a mount directory in /Volumes, and then mount the partition. The commands below are for a partition that is the first on disk2, for example.

  • Determine the disk number of the device and partition that you hve attached. Start Disk Utility and find your ext2/3 device's partition icon (orange probably). Click on it and select Info. The disk number should read something like disk2s1.
  • To mount it:
sudo -s
mkdir /Volumes/linux
mount_ext2 -o rdonly -x /dev/disk2s1 /Volumes/linux
  • For desktop access:
    • Go to the Finder Menu
    • Under Go, do Go->Go To Folder and type in /Volumes/linux , then press OK.

  • To unmount and confirm that it is unmounted:
umount /dev/disk2s1
df -Th




Problems, error messages, possible causes and possible fixes:

  • Mounting via the GUI in OS X using Ext2FSManager (in System Preferences) doesn't work. The most commond cause of this is that the ext2/3 filesystem that you are trying to mount wasn't unmounted correctly or it is not clean. You can:
    • let the fsck_ext2/3 that comes with ext2fsx try to automatically check and correct the problem (this will initiate automatically if it doesn't mount), or
    • kill the fsck_ext2/3 process that you see running and connect it to a Linux box and run fsck from there.

  • Invalid argument
mount_ext2: /dev/disk3s1 on /Volumes/linux: Invalid argument

If you are using a USB drive, this may mean that you forgot to unmount (see the Unmount section above) before physically disconnecting your cable.

  • No such directory
/dev/disk3s1 on /Volumes/linux: No such file or directory

You may have forgotten to create the mount point directory in /Volumes.

References and Links