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Recovering the root Password in AIX

Technote (FAQ)


Recovering the root Password in AIX


The information in this document applies to AIX Versions 4 and 5. If you need additional details about booting your system into maintenance mode and starting a limited function maintenance shell, consult the product documentation or contact your AIX support center.

Recovering the root password

Booting microchannel systems into Service mode

To boot microchannel systems into Service mode, turn the key to the Maintenance position and press the yellow Reset button twice. You must boot from bootable media, such as an installation CD-ROM, installation tape or a bootable backup tape made via the mksysb command or the Sysback product of the correct level for this machine.

Booting PCI-based systems into Service mode

When booting a PowerPC into Service mode, cd0 or rmt0 must be before the hdisk in the bootlist. If not, change the bootlist at boot time. On some models, you can set the machine to use a default bootlist that includes both cd0 and rmt0. If a bootable CD or tape is in the CD-ROM or tape drive, the machine will boot from this device.

For most of the newer PCI-based models, selecting the default bootlist, with a bootable tape or CD loaded in the machine, causes the system to automatically boot from that device. Generally, the next menu on the screen asks the administrator to define the system console.

For all machines discussed here, if you are using a graphical terminal, you will use a function key such as F5. If you are using an ASCII terminal, use an equivalent number key such as 5. Use the numbers across the top of the keyboard, not the numbers on the numeric keypad. On ASCII terminals, the icons may not be displayed on the screen; the number can be pressed between the second and the third beeps, the second beep being a series of three clicks.

  1. If the system has a Service/Normal key, turn it to the Service position.
  2. With bootable media as the same version and level as the system, boot the system. The bootable media can be any ONE of the following:

    • Bootable CD-ROM
    • NON_AUTOINSTALL mksysb
    • Bootable Install Tape

    Follow the prompts to the Welcome to Base OS menu.

  3. Choose Start Maintenance Mode for System Recovery (Option 3). The next screen displays prompts for the Maintenance Menu. Choose option 1:
       Access a Root Volume Group

    The next screen prints a warning message and asks you to select 0 to continue. Select 0.

       0 Continue

    The next screen asks you to select the proper volume group. Select the proper volume group for your machine.

    The console will display information about rootvg and a menu with two options. Choose option 1:

       Access this volume group and start a shell

    NOTE: You can also accomplish step 3 by booting into Service Mode from a Sysback Systape.

    1. Choose Option 4 Utilities.
    2. Import the rootvg.
    3. Select hdisk.
    4. Import rootvg and mount the filesystems.
    5. When prompted with Rebuild the Boot LV? Choose No.
    6. You should now see the # prompt.
    7. Enter df. This will show that the root filesystems are mounted.

    If you receive errors from the preceding options, do not continue with the rest of this procedure. First correct the problem. If you need assistance correcting the problem, contact one of the following:

    • local branch office
    • your point of sale
    • your AIX support center

  4. Run the passwd command from the command prompt:
  5.    passwd
       Changing password for "root"
       root's New password:
       Enter the new password again:
  6. With the key in Normal position (if applicable), issue the reboot command:
  7.    sync;sync;sync;reboot

Historical Number


Document information

More support for: AIX family

Software version: 4.3, 5.1, 5.2, 5.3

Operating system(s): AIX

Reference #: T1000366

Modified date: 26 November 2008