zed: Add zedlet to power off slot when drive is faulted

[tonyhutter]

Motivation and Context

Have ZED turn off power to a drive if the drive becomes faulted.

Description

If ZED_POWER_OFF_ENCLOUSRE_SLOT_ON_FAULT is enabled in zed.rc, then power off the drive's slot in the enclosure if it becomes FAULTED. This can help silence misbehaving drives. This assumes your drive enclosure fully supports slot power control via sysfs.

How Has This Been Tested?

Force faulted a drive with zpool offline -f <pool> <vdev>. Observed the drive power down.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.

[AllKind]

for i in $(seq 1 20) ; do
	if [ "$(cat $ZEVENT_VDEV_ENC_SYSFS_PATH/power_status)" == "off" ] ; then
		break
	fi
	sleep 0.1
done

if [ $i == 20 ] ; then
	exit 5
fi

If the slot is powered off on the 20th attempt, then the script will still exit with code 5.

[tonyhutter]

@AllKind good catch - I just fixed it in my latest push with:

diff --git a/cmd/zed/zed.d/statechange-slot_off.sh b/cmd/zed/zed.d/statechange-slot_off.sh
index 1a369a15a..327b3ae5d 100755
--- a/cmd/zed/zed.d/statechange-slot_off.sh
+++ b/cmd/zed/zed.d/statechange-slot_off.sh
@@ -54,7 +54,7 @@ for i in $(seq 1 20) ; do
        sleep 0.1
 done
 
-if [ $i == 20 ] ; then
+if [ "$(cat $ZEVENT_VDEV_ENC_SYSFS_PATH/power_status)" == "off" ] ; then
        exit 5
 fi

[AllKind]

+if [ "$(cat $ZEVENT_VDEV_ENC_SYSFS_PATH/power_status)" == "off" ] ; then
        exit 5
 fi

shouldn't that be != "off" ?

[tonyhutter]

@AllKind whoops, you're right. I fixed it in my latest push.