chccwdev - modify generic attributes of channel attached
devices.
The chccwdev command is used to set generic attributes for devices
that are controlled by the common I/O subsystem. Attributes are set in the
order they are specified on the commandline except the online attribute
which is special.
If the same attribute is given more than one time the value that
was set last will be used. This is also true (while not that obvious) when
mixing the generic -a and the -e, -d,
-s"and -f arguments."
All attributes will be set in the following order:
- 1.
- All attributes except online. If the device is offline there will be no
error if the attribute doesn't exist.
- 2.
- Set the online attribute to the desired value ((forced) online or (safe)
offline).
- 3.
- Set all the attributes that havn't been set, yet. At this point invalid
attribute names will always cause an error.
If any error occurs the execution is terminated. So if using
ranges only devices before the current one have been modified. There is no
automatic rollback. All attributes that already have been changed will stay
that way.
- -h|--help
- Print help text.
- -v|--version
- Print the version of the s390-tools package and the command.
- -a|--attribute
<name>=<value>
- Try to set the attribute named name to the given value. After
writing the attribute it will be read to check whether the setting was
accepted.
- -e|--online
- Try to set the specified devices online.
- -f|--forceonline
- Same as online but for devices that support this (DASD devices), it can be
used to bring it online regardless of any reserved states.
- -d|--offline
- Try to set the specified devices offline. The --online, --forceonline,
--offline, and --safeoffline options are mutually exclusive.
- -s|--safeoffline
- DASD only: For each specified device, wait until all outstanding I/O
requests have completed, and then try to set the device offline. The
--online, --forceonline, --offline, and --safeoffline options are mutually
exclusive.
- <range> = <bus ID>[-<bus ID>]
- <bus ID> = ([0-9]+\.[0-9]+\.)?[0-9a-f]{1,4}
- Note that bus IDs specified in short form (i.e. without leading
"0.<n>.") will be interpreted as "0.0.<bus
ID>".
Example: "0192" becomes "0.0.0192".
chccwdev --online 0.0.0192,0.0.0195-0.0.0198
After completing all outstanding I/O requests for the
devices with bus ID 0.0.0192, 0.0.0195, 0.0.0196, 0.0.0197 and 0.0.0198, tries
to set the device offline.
chccwdev --attribute readonly=1 --attribute online=1
0.0.0192
This will try to set the device with bus ID 0.0.192
online with readonly attribute set to one (read-only mode).
chccwdev --attribute cmb_enable=1 0.0.0195-0.0.0198
Set the cmb_enable attribute of the devices 0.0.0195,
0.0.0196, 0.0.0197 and 0.0.0198 to one. This would for example activate the
usage of the channel measurement block facility.
chccwdev --safeoffline 0.0.0192,0.0.0195-0.0.0198
Will try to set the devices with bus ID 0.0.0192,
0.0.0195, 0.0.0196, 0.0.0197 and 0.0.0198 offline and finish all outstanding
I/O requests before.
This man-page was written by Stefan Bader <shbader@de.ibm.com>.