Using base device parameters for a logical boot device

6.10 LPAR mode z/VM guest

You can use parameters to supply the base device information to zipl directly.

The following command syntax for the base device parameters is used for logical boot devices. It extends the zipl syntax for creating a regular boot device.

Base device parameters

You must specify the following device information:

The device node <targetbase_node>

of the base device, either by using the standard device name or in form of the major and minor number, separated by a colon (:).

Example: The device node specification for the device might be /dev/dm-0 and the equivalent specification as major and minor numbers might be 253:0.

The device type

of the base device. The following specifications are valid:

LDL: for ECKD type DASD with the Linux® disk layout.
CDL: for ECKD type DASD with the compatible disk layout.
FBA: for FBA type DASD.
SCSI: for FCP-attached SCSI disks.

LDL and CDL only: The disk geometry <cylinders>,<heads>,<sectors>

of the base device in cylinders, heads, and sectors.

The block size <targetblocksize>

in bytes per block of the base device.

The offset <targetoffset>

in blocks between the start of the physical device and the start of the topmost logical device in the mapping hierarchy.

Figure 1 shows how to specify this information in a configuration file.

Figure 1. zipl syntax for preparing a logical device as a boot device- configuration file mode

[<section_name>]
image=<image>,<image_addr>
ramdisk=<ramdisk>,<initrd_addr>
parmfile=<parmfile>,<parm_addr>
parameters=<parameters>
target=<directory>
targetbase=<targetbase_node>
targettype=LDL|CDL|FBA|SCSI
# Next line for target types LDL and CDL only
targetgeometry=<cylinders>,<heads>,<sectors>
targetblocksize=<targetblocksize>
targetoffset=<targetoffset>

Example

The example command identifies the location of the kernel image as /boot/image-5, identifies the location of an initial RAM disk as /boot/initrd-5, specifies a kernel parameter file /boot/parmf-5, and writes the required boot loader code to /boot.

The command specifies the following information about the base device: the device node is /dev/dm-3, the device has the compatible disk layout, there are 6678 cylinders, there are 15 heads, there are 12 sectors, and the topmost logical device in the mapping hierarchy begins with an offset of 24 blocks from the start of the base device.

# zipl -i /boot/image-5 -r /boot/initrd-5 -p /boot/parmf-5 -t /boot --targetbase /dev/dm-3 \
# --targettype CDL --targetgeometry 6678,15,12 --targetblocksize=4096 --targetoffset 24

Note: Instead of using the continuation sign (\) at the end of the first line, you might want to specify the entire command on a single line.

An equivalent section in a configuration file might look like this example:

[boot5]
image=/boot/image-5
ramdisk=/boot/initrd-5
paramfile=/boot/parmf-5
target=/boot
targetbase=/dev/dm-3
targettype=CDL
targetgeometry=6678,15,12
targetblocksize=4096
targetoffset=24