CHCHP(8)

📛 NAME 📛

okay so bestie, this is the CHCHP(8) page from the System Manager's Manual — and the star is chchp, here to 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). no cap, that's lowkey convenient.

Heads up: 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 💅

vibe check each flag, bestie — every single one is here, fr fr.

• -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: 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: 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. ✨
• -V, --version — Print version number, then exit. 👑

🧪 EXAMPLES 🧪

the receipts, periodt — run these exactly, bestie:

• 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) — go give it a look, iykyk. 🦋

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🍓 and that's the chchp(8) tea! source/version: s390-tools; date: Mar 2007; footer manual tag: CHCHP(8). mwah 💋