Setting up the DCSS device driver

Red Hat Enterprise Linux 9.2 z/VM guest

Before you can load and use DCSSs, you must load the DCSS block device driver. Use the segments module parameter to load one or more DCSSs when the DCSS device driver is loaded.

DCSS module parameter syntax

Read syntax diagramSkip visual syntax diagrammodprobe dcssblk segments=,:<dcss>(local)
<dcss>
specifies the name of a DCSS as defined on the z/VM hypervisor. The specification for <dcss> is converted from ASCII to uppercase EBCDIC.
:
the colon (:) separates DCSSs within a set of DCSSs to be mapped to a single DCSS device. You can map a set of DCSSs to a single DCSS device if the DCSSs in the set form a contiguous memory space.

You can specify the DCSSs in any order. The name of the first DCSS you specify is used to represent the device under /sys/devices/dcssblk.

(local)
sets the access mode to exclusive-writable after the DCSS or set of DCSSs are loaded.
,
the comma (,) separates DCSS devices.

Examples

The following command loads the DCSS device driver and three DCSSs: DCSS1, DCSS2, and DCSS3. DCSS2 is accessed in exclusive-writable mode. 
# modprobe dcssblk segments="dcss1,dcss2(local),dcss3"
The following command loads the DCSS device driver and four DCSSs: DCSS4, DCSS5, DCSS6, and DCSS7. The device driver creates two DCSS devices. One device maps to DCSS4 and the other maps to the combined storage space of DCSS5, DCSS6, and DCSS7 as a single device. 
# modprobe dcssblk segments="dcss4,dcss5:dcss6:dcss7"