Formatting ESE DASD

Red Hat Enterprise Linux 8.6 LPAR mode z/VM guest KVM guest

You can use the dasdfmt command to format an ESE DASD.

About this task

A new ESE DASD always has 0 allocated capacity, shown in the space_allocated sysfs attribute. When data is written to the DASD, this value increases as the storage server allocates storage to this device.

If you re-use an ESE DASD, and run dasdfmt, by default any space already allocated is released to reset the allocated capacity to 0. With the --no-discard option you can avoid the release of the allocated space, for example, if you wish to keep all data on the DASD, but want to re-initialize the VTOC.

Procedure

The dasdfmt command recognizes ESE DASD and, by default, sets the mode to quick.

All storage allocated for the DASD on the storage server is discarded.

For example, to use the quick format mode for an ESE DASD with device node /dev/dasdc, issue:

# dasdfmt /dev/dasdc

Use the --no-discard option to keep the storage allocated:

# dasdfmt --no-discard /dev/dasdc

See dasdfmt - Format a DASD for detailed examples.

You can use mode=full to format the entire DASD. The entire available capacity is occupied.