Preparing a dump device

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7.1 LPAR mode z/VM guest

Use zipl with the -d (--dumpto) command-line option or with the dumpto= configuration-file option to prepare a DASD device, SCSI disk, or channel-attached tape dump device.

Figure 1. zipl command line syntax for preparing a dump device

1  zipl  -d  <dump_device>? ,<size>?  -n?  --no-compress?  (1)-P 
dump_debug=<level>
Notes:
  • 1 For SCSI dump devices only

To prepare a DASD device, SCSI disk, NVMe disk, or channel-attached tape dump device, you must specify:

The device node <dump_device>
of the DASD device, SCSI disk partition, NVMe disk partition, or channel-attached tape device to be prepared as a dump device. zipl deletes all data on the partition or tape and installs the boot loader code there.
Note:
  • If the dump device is an ECKD™ disk with fixed-block layout (LDL), a dump overwrites the dump utility. You must reinstall the dump utility before you can use the device for another dump.
  • If the dump device is a channel-attached tape, SCSI disk, NVMe disk, FBA disk, or ECKD disk with the compatible disk layout (CDL), you do not need to reinstall the dump utility after every dump.
  • If the dump device is an NVMe disk and depending on your HMC version, you might have to prepare a partition in namespace 1 to be able to trigger an LPAR dump from the HMC GUI.

For DASD dump devices, the CCW-type standalone dump is automatically compressed using zlib compression if the DFLTCC facility is available on the system.

Optionally, you can also specify:
An option -n
to suppress confirmation prompts to allow unattended processing (for example, from a script). This option is available on the command line only.
An option --no-compress
to suppress zlib compression for a CCW-type dump. Zlib compression is used by default for CCW-type single volume DASD standalone dump if the DFLTCC facility is available on the system.
An option --ldipl-dump
to install a list-directed dump record instead of a CCW-type dump.
A limit <size>
for the amount of memory to be dumped. The value is a decimal number that can optionally be suffixed with K for kilobytes, M for megabytes, or G for gigabytes. The value is rounded to the next megabyte boundary.

If you limit the dump size below the amount of memory that is used by the system to be dumped, the resulting dump is incomplete.

Note: For SCSI and NVMe dump devices, the "size" option is not available.
SCSI dump tool parameter:
dump_debug=<level>
sets the level of debug messages during the dump process. <level> is an integer in the range 1 - 6. Use higher numbers for more detailed messages. The default is 2.

DASD device, SCSI disk, NVMe disk, or channel-attached tape dump devices are not formatted with a file system so no target directory can be specified. See Using the Dump Tools, SC33-8412 for details about processing these dumps.

Figure 2 summarizes how to specify a DASD device, SCSI disk, or channel-attached tape dump configuration in a configuration file.

Figure 2. zipl syntax for preparing a dump device - configuration file mode
[<section_name>]
dumpto=<dump_device>,<size>

DASD examples

The following command prepares a CCW DASD partition /dev/dasdc1 as a dump device and suppresses confirmation prompts that require an operator response:

# zipl -d /dev/dasdc1 -n
An equivalent section in a configuration file might look like this example: 
[dumpdasd]
dumpto=/dev/dasdc1

There is no configuration file equivalent for option -n. To use this option for a DASD or tape dump configuration in a configuration file, it must be specified with the zipl command that processes the configuration.

If the configuration file is called /etc/myxmp.conf: 
# zipl -c /etc/myxmp.conf dumpdasd -n

The following command prepares an ECKD DASD partition /dev/disk/by-path/ccw-0.0.1004-part1 for list-directed dump:

# zipl --ldipl-dump -d /dev/disk/by-path/ccw-0.0.1004-part1

SCSI disk example

The following command prepares a SCSI disk partition /dev/mapper/36005076303ffd40100000000000020c0-part1 as a dump device:

# zipl -d /dev/mapper/36005076303ffd40100000000000020c0-part1
An equivalent section in a configuration file might look like this example: 
[dumpscsi]
dumpto=/dev/mapper/36005076303ffd40100000000000020c0-part1
If the configuration file is called /etc/myxmp.conf, the zipl command that processes the configuration would be: 
# zipl -c /etc/myxmp.conf dumpscsi

NVMe disk example

The following command prepares an NVMe disk partition /dev/nvme0n1p1 as a dump device:

# zipl -d /dev/nvme0n1p1
An equivalent section in a configuration file might look like this example: 
[dumpnvme]
dumpto=/dev/nvme0n1p1
If the configuration file is called /etc/myxmp.conf, the zipl command that processes the configuration would be: 
# zipl -c /etc/myxmp.conf dumpnvme