Installation guide

Chapter 27. 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 ne-
cessary 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 13, “Language Selection”), the installation pro-
gram 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 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 sys-
tem instead of exiting the shell.
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 instruc-
ted 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).
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