Box freezes at start-up displaying the message 'freeing unused kernel'

The netfence system boots but the boot process stops. The last message shown is "Freeing unused kernel memory". This mostly happens if the box is restarted unclean (by pressing reset or after a power breakdown). 

Further error messages output is not shown because the netfence system has been configured to use an attached serial console for screen output. All messages that are generated after the "Freeing unused kernel memory" notice are written to the serial console.

In all probability the netfence systems is either performing an automatic file system check or a manual file system check is required.

First please check whether there is HDD activity on the system or not. If there is massive HDD activity, the system is performing an automatic file system check. Wait until the check is done. The system will continue its boot process automatically.

If there is no HDD activity (or the system has no HDD activity light) connect to the system's serial console with the following parameters:
19200,8,n,1 flow control off you can see at the prompt that a manual file system check is required, perform the following steps:

1. Enter the root password at the command prompt.

2. Perform a manual file system check by entering the following commands:

For IDE HDD systems:

    /bin/umount /dev/hda1
    /bin/umount /dev/hda2

    /bin/umount /dev/hda3
    /bin/umount /dev/hda4
    /bin/umount /dev/hda5

ext2 file system:

    /sbin/fsck.ext2 -y /dev/hda1
    /sbin/fsck.ext2 -y /dev/hda2
    /sbin/fsck.ext2 -y /dev/hda3
    /sbin/fsck.ext2 -y /dev/hda4
    /sbin/fsck.ext2 -y /dev/hda5
    /sbin/fsck.ext2 -y /dev/hda6

ext3 file system:

    /sbin/fsck.ext3 -y /dev/hda1
    /sbin/fsck.ext3 -y /dev/hda2
    /sbin/fsck.ext3 -y /dev/hda3
    /sbin/fsck.ext3 -y /dev/hda4
    /sbin/fsck.ext3 -y /dev/hda5
    /sbin/fsck.ext3 -y /dev/hda6

For SCSI HDD systems:

    /bin/umount /dev/sda1
    /bin/umount /dev/sda2
    /bin/umount /dev/sda3
    /bin/umount /dev/sda4
    /bin/umount /dev/sda5

ext2 file system:

    /sbin/fsck.ext2 -y /dev/sda1
    /sbin/fsck.ext2 -y /dev/sda2
    /sbin/fsck.ext2 -y /dev/sda3
    /sbin/fsck.ext2 -y /dev/sda4
    /sbin/fsck.ext2 -y /dev/sda5
    /sbin/fsck.ext2 -y /dev/sda6

ext3 file system:

    /sbin/fsck.ext3 -y /dev/sda1
    /sbin/fsck.ext3 -y /dev/sda2
    /sbin/fsck.ext3 -y /dev/sda3
    /sbin/fsck.ext3 -y /dev/sda4
    /sbin/fsck.ext3 -y /dev/sda5
    /sbin/fsck.ext3 -y /dev/sda6