See bug 586576 for corresponding documentation in /usr/share/doc/anaconda-*/kickstart-docs.txt

Created attachment 426738 [details]
patch for Kickstart2.xml

patch for Kickstart2.xml

This request was evaluated by Red Hat Product Management for
inclusion in the current release of Red Hat Enterprise Linux.
Because the affected component is not scheduled to be updated in the
current release, Red Hat is unfortunately unable to address this
request at this time. Red Hat invites you to ask your support
representative to propose this request, if appropriate and relevant,
in the next release of Red Hat Enterprise Linux.

This request was evaluated by Red Hat Product Management for
inclusion in the current release of Red Hat Enterprise Linux.
Because the affected component is not scheduled to be updated in the
current release, Red Hat is unfortunately unable to address this
request at this time. Red Hat invites you to ask your support
representative to propose this request, if appropriate and relevant,
in the next release of Red Hat Enterprise Linux.

Thanks Jason for the patch.

Fixed in build 3.1-9:

=====================
ignoredisk (optional)
    Causes the installer to ignore the specified disks. This is useful if you use autopartition and want to be sure that some disks are ignored. For example, without ignoredisk, attempting to deploy on a SAN-cluster the kickstart would fail, as the installer detects passive paths to the SAN that return no partition table. The --only-use option specifies that only the disks listed will be used during installion.
    The ignoredisk option is also useful if you have multiple paths to your disks.
    The syntax is:

    ignoredisk --drives=drive1,drive2,...

    where driveN is one of sda, sdb,..., hda,... etc.

        *
          --only-use — specifies a list of disks for the installer to use. All other disks are ignored. For example, to use disk sda during installation and ignore all other disks:

          ignoredisk --only-use=sda

This request was evaluated by Red Hat Product Management for
inclusion in the current release of Red Hat Enterprise Linux.
Because the affected component is not scheduled to be updated in the
current release, Red Hat is unfortunately unable to address this
request at this time. Red Hat invites you to ask your support
representative to propose this request, if appropriate and relevant,
in the next release of Red Hat Enterprise Linux.

This request was erroneously denied for the current release of
Red Hat Enterprise Linux.  The error has been fixed and this
request has been re-proposed for the current release.

This request was evaluated by Red Hat Product Management for
inclusion in the current release of Red Hat Enterprise Linux.
Because the affected component is not scheduled to be updated in the
current release, Red Hat is unfortunately unable to address this
request at this time. Red Hat invites you to ask your support
representative to propose this request, if appropriate and relevant,
in the next release of Red Hat Enterprise Linux.