Creating a qeth group device

Red Hat Enterprise Linux 9.2 LPAR mode z/VM guest

Use the znetconf command to configure network devices. Alternatively, you can use the chzdev command or sysfs.

Before you begin

You must know the device bus-IDs that correspond to the read, write, and data subchannel of your OSA-Express CHPID in QDIO mode or HiperSockets™ CHPID as defined in the IOCDS of your mainframe.

Procedure

To create a qeth group device, either:

Issue the znetconf command to create and configure a group device. The command groups the correct bus-IDs for you and sets the device online.
Write the device numbers of the subchannel triplet to the sysfs group attribute to only define a group device.
Issue a command of the form:
```
# echo <read_device_bus_id>,<write_device_bus_id>,<data_device_bus_id> > /sys/bus/ccwgroup/drivers/qeth/group
```

Results

The qeth device driver uses the device bus-ID of the read subchannel to create a directory for a group device:

/sys/bus/ccwgroup/drivers/qeth/<read_device_bus_id>

This directory contains a number of attributes that determine the settings of the qeth group device. The following sections describe how to use these attributes to configure a qeth group device.

Example

In this example (see Figure 1), a single OSA-Express CHPID in QDIO mode is used to connect a Linux® instance to a network.

Mainframe configuration:

This graphic is described in the surrounding text. — Figure 1. Mainframe configuration

Linux configuration:

Assuming that 0.0.aa00 is the device bus-ID that corresponds to the read subchannel:

# echo 0.0.aa00,0.0.aa01,0.0.aa02 > /sys/bus/ccwgroup/drivers/qeth/group

This command results in the creation of the following directories in sysfs:

/sys/bus/ccwgroup/drivers/qeth/0.0.aa00
/sys/bus/ccwgroup/devices/0.0.aa00
/sys/devices/qeth/0.0.aa00

Both the command and the resulting directories would be the same for a HiperSockets CHPID.