mirror_zfs/cmd/zed/zed.d/deadman-slot_off.sh
Brian Behlendorf 6b95031f56
zed: Add deadman-slot_off.sh zedlet
Optionally turn off disk's enclosure slot if an I/O is hung
triggering the deadman.

It's possible for outstanding I/O to a misbehaving SCSI disk to
neither promptly complete or return an error.  This can occur due
to retry and recovery actions taken by the SCSI layer, driver, or
disk.  When it occurs the pool will be unresponsive even though
there may be sufficient redundancy configured to proceeded without
this single disk.

When a hung I/O is detected by the kmods it will be posted as a
deadman event.  By default an I/O is considered to be hung after
5 minutes.  This value can be changed with the zfs_deadman_ziotime_ms
module parameter.  If ZED_POWER_OFF_ENCLOSURE_SLOT_ON_DEADMAN is set
the disk's enclosure slot will be powered off causing the outstanding
I/O to fail.  The ZED will then handle this like a normal disk failure.
By default ZED_POWER_OFF_ENCLOSURE_SLOT_ON_DEADMAN is not set.

As part of this change `zfs_deadman_events_per_second` is added
to control the ratelimitting of deadman events independantly of
delay events.  In practice, a single deadman event is sufficient
and more aren't particularly useful.

Alphabetize the zfs_deadman_* entries in zfs.4.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #16226
2024-05-29 10:46:41 -07:00

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#!/bin/sh
# shellcheck disable=SC3014,SC2154,SC2086,SC2034
#
# Turn off disk's enclosure slot if an I/O is hung triggering the deadman.
#
# It's possible for outstanding I/O to a misbehaving SCSI disk to neither
# promptly complete or return an error. This can occur due to retry and
# recovery actions taken by the SCSI layer, driver, or disk. When it occurs
# the pool will be unresponsive even though there may be sufficient redundancy
# configured to proceeded without this single disk.
#
# When a hung I/O is detected by the kmods it will be posted as a deadman
# event. By default an I/O is considered to be hung after 5 minutes. This
# value can be changed with the zfs_deadman_ziotime_ms module parameter.
# If ZED_POWER_OFF_ENCLOSURE_SLOT_ON_DEADMAN is set the disk's enclosure
# slot will be powered off causing the outstanding I/O to fail. The ZED
# will then handle this like a normal disk failure and FAULT the vdev.
#
# We assume the user will be responsible for turning the slot back on
# after replacing the disk.
#
# Note that this script requires that your enclosure be supported by the
# Linux SCSI Enclosure services (SES) driver. The script will do nothing
# if you have no enclosure, or if your enclosure isn't supported.
#
# Exit codes:
# 0: slot successfully powered off
# 1: enclosure not available
# 2: ZED_POWER_OFF_ENCLOSURE_SLOT_ON_DEADMAN disabled
# 3: System not configured to wait on deadman
# 4: The enclosure sysfs path passed from ZFS does not exist
# 5: Enclosure slot didn't actually turn off after we told it to
[ -f "${ZED_ZEDLET_DIR}/zed.rc" ] && . "${ZED_ZEDLET_DIR}/zed.rc"
. "${ZED_ZEDLET_DIR}/zed-functions.sh"
if [ ! -d /sys/class/enclosure ] ; then
# No JBOD enclosure or NVMe slots
exit 1
fi
if [ "${ZED_POWER_OFF_ENCLOSURE_SLOT_ON_DEADMAN}" != "1" ] ; then
exit 2
fi
if [ "$ZEVENT_POOL_FAILMODE" != "wait" ] ; then
exit 3
fi
if [ ! -f "$ZEVENT_VDEV_ENC_SYSFS_PATH/power_status" ] ; then
exit 4
fi
# Turn off the slot and wait for sysfs to report that the slot is off.
# It can take ~400ms on some enclosures and multiple retries may be needed.
for i in $(seq 1 20) ; do
echo "off" | tee "$ZEVENT_VDEV_ENC_SYSFS_PATH/power_status"
for j in $(seq 1 5) ; do
if [ "$(cat $ZEVENT_VDEV_ENC_SYSFS_PATH/power_status)" == "off" ] ; then
break 2
fi
sleep 0.1
done
done
if [ "$(cat $ZEVENT_VDEV_ENC_SYSFS_PATH/power_status)" != "off" ] ; then
exit 5
fi
zed_log_msg "powered down slot $ZEVENT_VDEV_ENC_SYSFS_PATH for $ZEVENT_VDEV_PATH"