Move the shelf ramp above the drives' working range, add a deadband
Retiring 8x2TB for 4x8TB + a 16TB moved the hottest drive to 40-41c, exactly the old 40c ramp start, and the fan flipped 10<->15% every 30 seconds. The ramp is now 44-56c, which puts the drives back on the floor with 19c of headroom to their 60c limit. Adds the deadband from fan_speed.sh so the shelf does not chase every degree once drives do climb into the ramp, with a downward-only periodic settle so damping cannot leave it permanently loud. selftest and disks no longer take the serial lock - they do not open the port, and refusing to run them while the service is up is unhelpful. The new tests caught a real bug: in `local a=$1 b=$a` bash expands the right-hand sides before the locals exist, so the held value was silently empty. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
Zeb Hering
22
README.md
22
README.md
@@ -113,14 +113,28 @@ All knobs are at the top of `das_fanctl.sh`:
|
||||
| `PORT` | `/dev/ttyS1` | Serial device the service cable lands on |
|
||||
| `CHECK_INTERVAL` | `30` | Seconds between temperature readings |
|
||||
| `KEEPALIVE_INTERVAL` | `5` | How often to re-send `_shutup` |
|
||||
| `DISK_LOW_TEMPERATURE_THRESHOLD` | `40` | At/below this, run at `LOW_FAN_SPEED` |
|
||||
| `DISK_HIGH_TEMPERATURE_THRESHOLD` | `50` | At/above this, run at `HIGH_FAN_SPEED` |
|
||||
| `DISK_LOW_TEMPERATURE_THRESHOLD` | `44` | At/below this, run at `LOW_FAN_SPEED` |
|
||||
| `DISK_HIGH_TEMPERATURE_THRESHOLD` | `56` | At/above this, run at `HIGH_FAN_SPEED` |
|
||||
| `FAN_SPEED_DEADBAND` | `8` | Hold the current speed until the request moves this far |
|
||||
| `SETTLE_INTERVAL` | `300` | Allow a downward settle this often |
|
||||
| `LOW_FAN_SPEED` | `10` | Percent |
|
||||
| `HIGH_FAN_SPEED` | `60` | Percent |
|
||||
| `BP_*_THRESHOLD` | `30` / `45` | Fallback curve, backplane air sensors |
|
||||
|
||||
The defaults were sized against an idle spread of 32–39c across nine mixed SATA/SAS
|
||||
drives. Your airflow is not that airflow — watch a day of log before trusting them.
|
||||
**Start the ramp above the drives' normal working range.** This is the single most
|
||||
common way to make a shelf cycle audibly: if the ramp starts inside the range the drives
|
||||
already occupy, ordinary drift crosses it and the fans flip every cycle. The curve is
|
||||
~4%/degC, so one degree moves the fan noticeably.
|
||||
|
||||
Worked example: the original 40–50c was sized for 8×2TB drives idling at 32–39c. Retiring
|
||||
those for 4×8TB + a 16TB moved the hottest drive to 40–41c — exactly the old ramp start —
|
||||
and the fan flipped 10↔15% every 30 seconds (18 samples at 10, 22 at 15). Moving the ramp
|
||||
to 44–56c put the drives back on the floor: 11 consecutive samples at 10%, and they still
|
||||
have 19c of headroom to their 60c limit.
|
||||
|
||||
`FAN_SPEED_DEADBAND` damps what remains, so once drives do climb into the ramp it does not
|
||||
chase every degree. A settle is permitted every `SETTLE_INTERVAL`, downward only —
|
||||
a symmetric deadband would catch the fan on the way up and never let it back down.
|
||||
|
||||
`KEEPALIVE_INTERVAL` is inherited from the 5s cadence the original setup used, not
|
||||
measured. How fast the EMM actually reverts is unknown; if the fans audibly surge
|
||||
|
||||
@@ -21,20 +21,59 @@ HIGH_FAN_SPEED=60
|
||||
# internal drives sit on pci-0000:02:00.0 while the shelf is on 04:00.0. Name the
|
||||
# shelf's HBA explicitly on any host with more than one.
|
||||
DISK_GLOB=${DISK_GLOB:-/dev/disk/by-path/*-sas-exp*-lun-0}
|
||||
DISK_LOW_TEMPERATURE_THRESHOLD=40 # at/below this -> LOW_FAN_SPEED (idle spread is 32-39c)
|
||||
DISK_HIGH_TEMPERATURE_THRESHOLD=50 # at/above this -> HIGH_FAN_SPEED
|
||||
# The ramp must START ABOVE the drives' normal working range, or every degree of
|
||||
# ordinary drift crosses it and the fans cycle audibly. The 4x8TB + 1x16TB set in
|
||||
# this shelf works at 30-41c against a 60c limit, so 44 leaves 3c of clearance.
|
||||
# The previous 40-50c was sized for an 8x2TB set that idled at 32-39c; the newer
|
||||
# drives run warmer and sat exactly on the old ramp start, flipping 10<->15%
|
||||
# every 30 seconds.
|
||||
DISK_LOW_TEMPERATURE_THRESHOLD=${DISK_LOW_TEMPERATURE_THRESHOLD:-44}
|
||||
DISK_HIGH_TEMPERATURE_THRESHOLD=${DISK_HIGH_TEMPERATURE_THRESHOLD:-56}
|
||||
|
||||
# Backplane air sensors, only used when no disk will answer (all spun down, smartctl gone)
|
||||
BP_LOW_TEMPERATURE_THRESHOLD=30
|
||||
BP_HIGH_TEMPERATURE_THRESHOLD=45
|
||||
|
||||
# Hold the current speed unless the request moves this far. The curve is ~4%/degC
|
||||
# even after widening, so without damping a single degree of drive drift moves the
|
||||
# fan. A re-settle is allowed periodically, downward only - see settle_fan_speed.
|
||||
FAN_SPEED_DEADBAND=${FAN_SPEED_DEADBAND:-8}
|
||||
SETTLE_INTERVAL=${SETTLE_INTERVAL:-300}
|
||||
|
||||
SPEED=$LOW_FAN_SPEED
|
||||
SPEED_SET_AT=0
|
||||
|
||||
# Only one talker on the serial line (detach screen/attachDAS.sh first)
|
||||
# Only one talker on the serial line (detach screen/attachDAS.sh first). Taken
|
||||
# only by the subcommands that actually open the port - selftest and disks do
|
||||
# not, and refusing to run them while the service is up is just unhelpful.
|
||||
claim_serial_port() {
|
||||
exec 9>/run/das_fanctl.lock
|
||||
flock -n 9 || { echo "another das_fanctl is running (or /dev/ttyS1 is busy)" >&2; exit 1; }
|
||||
|
||||
flock -n 9 || { echo "another das_fanctl is running (or $PORT is busy)" >&2; exit 1; }
|
||||
stty -F $PORT 38400 raw -echo -echoe -echok -echoctl -echoke
|
||||
}
|
||||
|
||||
# True when the request has moved far enough to act on. Full speed is never held back.
|
||||
fan_speed_changed_enough() {
|
||||
local wanted=$1 applied=$2 delta
|
||||
[ "$wanted" -ge "$HIGH_FAN_SPEED" ] && return 0
|
||||
delta=$((wanted - applied)); [ "$delta" -lt 0 ] && delta=$((-delta))
|
||||
[ "$delta" -ge "$FAN_SPEED_DEADBAND" ]
|
||||
}
|
||||
|
||||
# settle_fan_speed <wanted> <applied> <settle due, 0|1>
|
||||
# A symmetric deadband catches the fan on the way up and never lets it back down,
|
||||
# which leaves the shelf permanently louder than it needs to be. So periodically -
|
||||
# and only downward - let it settle to what is actually wanted. Upward moves always
|
||||
# require a full deadband crossing.
|
||||
settle_fan_speed() {
|
||||
local wanted=$1 applied=$2 due=$3
|
||||
# Declared separately on purpose: in `local a=$1 b=$a` the right-hand sides are
|
||||
# expanded before the locals exist, so b would get the OUTER scope's a (empty).
|
||||
local target=$applied
|
||||
fan_speed_changed_enough "$wanted" "$applied" && target=$wanted
|
||||
if [ "$due" = 1 ] && [ "$wanted" -lt "$target" ]; then target=$wanted; fi
|
||||
echo "$target"
|
||||
}
|
||||
|
||||
# Fire and forget - the DAS answers with a bare prompt, nothing worth reading
|
||||
set_fan() { printf '_shutup %s\r' "$1" > $PORT; }
|
||||
@@ -89,10 +128,17 @@ one_pass() {
|
||||
low=$BP_LOW_TEMPERATURE_THRESHOLD; high=$BP_HIGH_TEMPERATURE_THRESHOLD
|
||||
fi
|
||||
|
||||
SPEED=$(calculate_interpolated_fan_speed "$temp" $low $high $LOW_FAN_SPEED $HIGH_FAN_SPEED)
|
||||
local want now due=0 prev=$SPEED held=""
|
||||
want=$(calculate_interpolated_fan_speed "$temp" $low $high $LOW_FAN_SPEED $HIGH_FAN_SPEED)
|
||||
now=$(date +%s)
|
||||
[ $((now - SPEED_SET_AT)) -ge "$SETTLE_INTERVAL" ] && due=1
|
||||
SPEED=$(settle_fan_speed "$want" "$SPEED" "$due")
|
||||
{ [ "$SPEED" != "$prev" ] || [ "$due" = 1 ]; } && SPEED_SET_AT=$now
|
||||
[ "$SPEED" = "$want" ] || held=" held, want $want"
|
||||
|
||||
set_fan "$SPEED"
|
||||
echo "$(date +'%Y-%m-%d %H:%M:%S') || DAS ${source}:${temp}c | Fan Speed:$SPEED" >> $LOG
|
||||
echo "DAS ${source}:${temp}c -> fan ${SPEED}%"
|
||||
echo "$(date +'%Y-%m-%d %H:%M:%S') || DAS ${source}:${temp}c | Fan Speed:${SPEED}${held}" >> $LOG
|
||||
echo "DAS ${source}:${temp}c -> fan ${SPEED}%${held}"
|
||||
}
|
||||
|
||||
selftest() {
|
||||
@@ -107,9 +153,21 @@ selftest() {
|
||||
[ "$(calculate_interpolated_fan_speed 55 40 50 10 60)" = 60 ] || { echo "FAIL: high clamp"; exit 1; }
|
||||
[ "$(calculate_interpolated_fan_speed 45 40 50 10 60)" = 35 ] || { echo "FAIL: midpoint"; exit 1; }
|
||||
[ "$(hottest_disk)" -gt 0 ] || { echo "FAIL: no disk temperatures readable"; exit 1; }
|
||||
HIGH_FAN_SPEED=60
|
||||
[ "$(settle_fan_speed 15 10 0)" = 10 ] || { echo "FAIL: 5% drift should hold"; exit 1; }
|
||||
[ "$(settle_fan_speed 18 10 0)" = 18 ] || { echo "FAIL: 8% rise should be adopted"; exit 1; }
|
||||
[ "$(settle_fan_speed 60 10 0)" = 60 ] || { echo "FAIL: full speed always adopted"; exit 1; }
|
||||
[ "$(settle_fan_speed 26 30 0)" = 30 ] || { echo "FAIL: small fall should hold"; exit 1; }
|
||||
[ "$(settle_fan_speed 26 30 1)" = 26 ] || { echo "FAIL: should settle down when due"; exit 1; }
|
||||
[ "$(settle_fan_speed 34 30 1)" = 30 ] || { echo "FAIL: must not drift up on a settle"; exit 1; }
|
||||
echo "selftest OK"
|
||||
}
|
||||
|
||||
case "${1:-loop}" in
|
||||
selftest|disks) ;; # no serial access
|
||||
*) claim_serial_port ;;
|
||||
esac
|
||||
|
||||
case "${1:-loop}" in
|
||||
temps) das_cmd _temp_rd ;;
|
||||
disks) for l in $DISK_GLOB; do
|
||||
|
||||
Reference in New Issue
Block a user