This is my write up of how I now use Home Assistant to manage my external hard disks, manage their temperatures, uptime and overall extend their lifespans with some work arounds and cobbled together ideas. This might inspire you to do the same.
Firstly my setup. I run Home Assistant in a VM (Virtualbox), running on a windows host. Because of this, most of my challenges have been around how to get data into HA from data on the host.
Chapter One, hard disk SMART INFO.
I started with hard disk temperatures. On the host I run CrystalDiskInfo, which was showing some of my drives were getting warm. I had an old USB fan kicking around so plugged it in and the temperatures came right down. So my first thought was how to get those temperatures into HA, and control the on/off of the fan via a smart plug.
This is the route I took…
I downloaded GSmartControl which is a windows GUI on the excellent linux command line smartctl program that can output the SMART info for any hard disk that supports it.
Using the windows port of the command line version of the tool that comes with the windows GUI, I narrowed down the hard disk I wanted to monitor (you could do many if you wish).
Simply using an elevated windows command prompt, I was able to scan all the drives I had and create the following batch file:
@echo off
cd C:\utils\gsmartcontrol-1.1.4-win64
smartctl -A /dev/sde > c:\utils\RebexTinyWebServer\wwwroot\smarthddinfo.txt
REM Wait 10 seconds to make AlwaysUp stop complaining that the script has finished too quickly.
timeout /t 10
exit /b
I keep this batch file in the same folder as the smartctl executable, but you could put it where ever you like.
What this script does is outputs the SMART info of a specific drive (sde) and pipes that output into a text file in another folder. This is an example of the output:
smartctl 7.2 2020-12-30 r5155 [x86_64-w64-mingw32-w10-b22621] (sf-7.2-1)
Copyright (C) 2002-20, Bruce Allen, Christian Franke, www.smartmontools.org
=== START OF READ SMART DATA SECTION ===
SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
1 Raw_Read_Error_Rate 0x000b 100 100 016 Pre-fail Always - 0
2 Throughput_Performance 0x0004 130 130 054 Old_age Offline - 108
3 Spin_Up_Time 0x0007 213 213 024 Pre-fail Always - 293 (Average 324)
4 Start_Stop_Count 0x0012 100 100 000 Old_age Always - 13
5 Reallocated_Sector_Ct 0x0033 100 100 005 Pre-fail Always - 0
7 Seek_Error_Rate 0x000a 100 100 067 Old_age Always - 0
8 Seek_Time_Performance 0x0004 128 128 020 Old_age Offline - 18
9 Power_On_Hours 0x0012 100 100 000 Old_age Always - 314
10 Spin_Retry_Count 0x0012 100 100 060 Old_age Always - 0
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 8
22 Helium_Level 0x0023 100 100 025 Pre-fail Always - 100
192 Power-Off_Retract_Count 0x0032 100 100 000 Old_age Always - 25
193 Load_Cycle_Count 0x0012 100 100 000 Old_age Always - 25
194 Temperature_Celsius 0x0002 147 147 000 Old_age Always - 44 (Min/Max 18/52)
196 Reallocated_Event_Count 0x0032 100 100 000 Old_age Always - 0
197 Current_Pending_Sector 0x0022 100 100 000 Old_age Always - 0
198 Offline_Uncorrectable 0x0008 100 100 000 Old_age Offline - 0
199 UDMA_CRC_Error_Count 0x000a 200 200 000 Old_age Always - 0
Next, I had to make sure that data was up to date, so created a windows scheduled task to execute the batch file every 3 minutes. That did the trick. You’ll need to run the task with elevated permissions for smartctl to work properly.
Now I had the data, I needed to get it into HA.
I first looked at using a file sensor, or a command line sensor and copy the the file into an SMB share inside the VM that HA could get at, but both had limitations.
What I ended up with was using a very light weight webserver called Rebex, which you can download here:
You’ll notice that the batch file above, puts its output text file into a folder called wwwroot in the rebex folder. This means I can then grab that file via an HTTP call in HA. So I setup a rest sensor like so:
- platform: rest
name: main_hdd_temperature_restful
scan_interval: 180
resource: http://192.168.0.200:1180/smarthddinfo.txt
value_template: >
{% if "Temperature_Celsius" in value %}
{{ value.split("Temperature_Celsius")[1].split("(")[0].split("-")[1] }}
{%else%}
99
{%endif%}
This grabs the data from the Temperature_Celsius line and (in the example above), extracts the value 44. It does this once every 3 minutes.
I now have the temperature updating regularly in HA!:
Next, I setup a pretty simple automation to control the fan pointed at the hard disk:
alias: Home Server - HDD Fan Control
description: ""
trigger:
- platform: state
entity_id:
- sensor.main_hdd_temperature_restful
condition: []
action:
- if:
- condition: numeric_state
entity_id: sensor.main_hdd_temperature_restful
above: 45
then:
- type: turn_on
device_id: 956725bc947f0414fa6e41ca785ee017
entity_id: switch.tradfri_plug_hdd_fan_switch
domain: switch
else: []
- if:
- condition: numeric_state
entity_id: sensor.main_hdd_temperature_restful
below: 43
then:
- type: turn_off
device_id: 956725bc947f0414fa6e41ca785ee017
entity_id: switch.tradfri_plug_hdd_fan_switch
domain: switch
else: []
mode: single
You could use this method to grab pretty much any data and get it into HA.
Next Chapter…
Managing the power on the hard disks and spinning these up and down as required.
