Red Hat ENTERPRISE LINUX 5 - VIRTUAL SERVER ADMINISTRATION, Installation Manual

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Chapter 28.
283
Rescue Mode on POWER Systems
You can use the installation disks in rescue mode, in case your system does not boot. Rescue mode
gives you access to the disk partitions on your system so you can make any changes necessary to
rescue your installation.
To boot in rescue mode on IBM System i with power control NWSD , follow the instructions for booting
the installation program, with this change: In the NWSD, set the IPL parameters field to
'rescue'
(including the quotes), or to
'dd rescue'
if you need to load the SCSI driver. On other systems,
specify the
rescue
or
dd rescue
(without quotes) after the default kernel name at the YABOOT
prompt.
After the Language Selection screen (
Section 12.13, “Language Selection”
), the installation program
attempts to mount the disk partitions on your system. It then presents you with a shell prompt where
you can make the changes you need. These changes may include storing the kernel and command
line into the IPL source, as described in the Installation Complete section (
Section 12.26, “Installation
Complete”
).
When your changes are complete, you can exit the shell using
exit 0
. This causes a reboot from the
C side. To reboot from the A or B side or from *NWSSTG, you should vary off the system instead of
exiting the shell.
28.1. Special Considerations for Accessing the SCSI
Utilities from Rescue Mode
If your system uses Native DASD disks, you may need access to the SCSI utilities from rescue mode.
These utilities are located on the driver disc CD. The driver disc CD cannot be mounted from rescue
mode unless special steps are taken. These steps are described below.
If you have a second CD-ROM drive assigned to your Linux system, you can mount the driver disc CD
in the second drive.
If you have only one CD-ROM drive, you must set up an NFS boot, using the following steps:
1. Boot from the CD-ROM with the
linux rescue askmethod
command. This allows you to
manually select NFS as the source of your rescue media instead of defaulting to the CD-ROM
drive.
2. Copy the first installation disc onto a file system of another Linux system.
3. Make this copy of the installation disc available through NFS or FTP.
4. Vary off or power down the system you need to rescue. Set its IPL parameters as instructed for
booting the Installation discs in rescue mode, except that the IPL source should point to the copy
of
boot.img
on your IFS (from step 1, above).
5.
Make sure the installation disc is not in your CD-ROM drive.
6. IPL the Linux system.
7. Follow the prompts as decribed in
Chapter 28, Rescue Mode on POWER Systems
. An additonal
prompt for the installation source appears. Select NFS or FTP (as appropriate) and complete the
following network configuration screen.