Man pages sections > man8 > chchp

chchp - modify channel-path state.

CHCHP(8) System Manager's Manual CHCHP(8)

NAME

chchp - modify channel-path state.
 

SYNOPSIS

chchp [-v|--vary value] [-c|--configure value]
 
[-a|--attribute key=value] chpid
 
[-h|--help] [--version]
 

DESCRIPTION

The chchp command modifies the state of one or more channel-paths. Channel-path identifiers are specified in hexadecimal notation either simply as the CHPID-number (e.g. e0) or in the form
 
<cssid>.<id>
 
where <cssid> is the channel-subsystem identifier and <id> is the CHPID-number (e.g. 0.7e).
 
An operation can be performed on more than one channel-path by specifying multiple identifiers as a blank or comma-separated list or a range or a combination of both (see EXAMPLES section).
 
Note that modifying the state of channel-paths can affect the availability of I/O devices as well as trigger associated functions (e.g. channel-path verification or device scanning) which in turn can result in a temporary increase in processor, memory and I/O load.

OPTIONS

-v value
 
--vary value
Change the logical channel-path state to value. The logical channel-path state determines whether Linux will be actively using a channel-path for I/O.
 
 
A value of "0" specifies the logical offline state. A value of "1" specifies the logical online state.
 
 
Note that setting the logical state to offline may cause a currently running I/O operation to be aborted.
 
-c value
 
--configure value
Change the channel-path configuration state to value.
 
 
A value of "0" specifies standby state. A value of "1" specifies configured state.
 
 
Note that setting the configured state to standby may cause a currently running I/O operation to be aborted.
 
-a key=value
 
--attribute key=value
Change the channel-path sysfs attribute key to value.
 
 
key can be the name of any available channel-path sysfs attribute (e.g. "configure" or "status"), while value can take any valid value that may be written to the attribute (e.g. "0" or "offline").
 
 
This is a more generic way of modifying the state of a channel-path via the sysfs interface. It is intended for cases where sysfs attributes or attribute values are available in the kernel but not in chchp.
 
 
-h
 
--help
Print a short help text, then exit.
 
--version
Print version number, then exit.
 

EXAMPLES

chchp -c 0 19
Put channel-path 0.19 into standby state.
 
chchp -a configure=0 19
Write value "0" into sysfs attribute "configure" of channel-path 0.19. The result is the same as when using the command chchp -c 0 19
 
chchp -c 1 0.65-0.6f
Put channel-paths 0.65 to 0.6f into configured state.
 
chchp -v 0 0.12,0.7f,0.17-0.20
Put channel-paths 0.12, 0.7f and 0.17 to 0.20 into logical offline state.
 

SEE ALSO

lschp(8)
Mar 2007 s390-tools