Differences

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--- doc:appunti:hardware:raspberrypi_nas_smart_hard_disk [2021/04/16 17:17] – [hdparm] niccolo
+++ doc:appunti:hardware:raspberrypi_nas_smart_hard_disk [2025/10/10 11:24] (current) – [udisks2.service] niccolo
@@ Line 1: / Line 1: @@
 ====== Raspberry Pi NAS: Hard disk management ======
-This page is about configuring the **hard disk power management** on a Raspberry Pi, to be used as NAS and mediacenter. The hard disk is connected via a **[[raspberrypi_nas_x835_sata_board|SupTronics X835 shield]]**. See the main index at **[[raspberrypi_nas]]**.
+This page is about configuring the **hard disk power management** on a Raspberry Pi, to be used as NAS and mediacenter. The hard disk is connected via a **[[raspberrypi_nas_x835_sata_board|SupTronics X835 shield]]**. See the main index at **[[raspberrypi_nas]]**. The operating system is **RaspiOS** based on **Debian 11 Bullseye**.
 There are two tools to manage SATA disks in GNU/Linux. **smartctl** is designed to interact with the **[[wp>S.M.A.R.T.]]** capabilities of a disk. **hdparm** is a command line interface to the Linux kernel SATA subsystem, including Advanced Power Management.
@@ Line 93: / Line 93: @@
 ===== hdparm =====
-To set the **Advanced Power Management** level use the **%%-B%%** option, the maximum performance level which **permits spin-down** of the drive is 127:
+To set the **Advanced Power Management** level use the **%%-B%%** option. A low value means aggressive power management, an high value means better performance. The maximum performance level which **permits spin-down** of the drive is 127:
 <code>
@@ Line 113: / Line 113: @@
 </code>
-Debian provides the file **/etc/hdparm.conf** which is handled by the **udev** on system start to set the required parameters. You can set something like this:
+Debian provides the file **/etc/hdparm.conf** which is handled by the **udev** on **system start** to set the required parameters. You can set something like this:
 <file>
@@ Line 119: / Line 119: @@
 # It is advisable to disable write cache in this case.
 # See man hdparm(8), -S and -W options.
+# The granularity of the spindown_time up to 20 minutes is 5
+# seconds, above that threshold it is 30 minutes.
 /dev/sda {
         write_cache = off
@@ Line 158: / Line 160: @@
   * **updatedb** - Execute by the **/etc/cron.daily/mlocate** cronjob, will update the database of files stored on hard disk. Add the directory to be skipped into **/etc/updatedb.conf**.
-  * **smartctl** - Reading SMART attributes (e.g. disk temperature, errors log) awake the disk. Hou may have periodic checks executed by **snmpd**, etc.
+  * **smartctl** - Reading SMART attributes (e.g. disk temperature, errors log) awake the disk. You may have periodic checks executed by **snmpd**, etc.
+===== udisks2.service =====
+It seems that the **udisks2.service** may interfere with the hard disk spin-down feature. The ''man 8 udisks'' refers to setting APT options (//StandbyTimeout//, //APMLevel//, ...) via ATA commands.
+It is likely that the hdparm options set by **udev** on system start are overridden by udisks2. In a [[..:software:kodi_installation_raspios_13|system based on RaspiOS 13 Trixie]] I had to remove the **udisks2** package to allow the hard drive to go into standby mode as epxlained above.
+Some useful udisks2 commands:
+<code>
+udisksctl info -b /dev/sda3
+</code>
 ===== Web References =====