Boot from the A and B IPL source

 

A logical partition running Linux can start from either the A or B IPL source.

Linux must be installed on the server and previously loaded from a different source before this option can be used. Administration authority must be obtained before performing this task. For more information on how to configure user profiles, refer to Logical partition authority for more information. To copy a kernel into the A or B IPL source, the /proc file system is used. The command used to copy the kernel into the A IPL source is dd if=/path/to/vmlinux of=/proc/iSeries/mf/A/vmlinux bs=4096. The command used to copy the kernel into the B IPL source is dd if=/path/to/vmlinux of=/proc/iSeries/mf/B/vmlinux bs=4096. The advantage of using this start source is that Linux starts faster. A disadvantage is that the start source cannot be saved or restored. It is also difficult to tell which IPL source has stored the kernel. If you need to pass arguments to the kernel during start, you can modify the kernel command line parameters either through the Work with partitions service tool on your i5/OS® primary partition or through the /proc file system under Linux. Follow these steps to set the kernel command line:

  1. At the i5/OS command line, type STRSST and press Enter.

  2. From the Start Service Tools (STRSST) Sign On display, provide the Service Tools user ID and password and press Enter. For more information on how to configure user profiles, refer to Logical partition authority for more information.

  3. From the System Service Tools (SST) display, select option 5 (Work with servers) and press Enter.

  4. From the Work with System Partitions display, select option 3 (Work with partition configuration) and press Enter.

  5. From the Work with Partition configuration display, select option 14 (Change logical commands) next to the logical partition you want to modify and press Enter.

  6. From the Change Guest Environment Command Line Parameters display, enter the new kernel command and press Enter.

To set the kernel command line through the /proc file system for the A IPL source, use a variation of the following command: echo -n "root=/dev/iSeries/vda1" >> /proc/iSeries/mf/A/cmdline

To set the kernel command line through the /proc file system for the B IPL source, use a variation of the following command: echo -n "root=/dev/iSeries/vda1" >> /proc/iSeries/mf/B/cmdline

 

Parent topic:

Start a logical partition