Disabling SATA disk and scanning for it

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1

An annoying kernel bug delays resume from suspend to RAM: https://bugzilla.opensuse.org/show_bug.cgi?id=1195025 As a workaround the HDD involved is deactivated on suspend.

Scripts:

The dirty hack works as long as the HDD is plugged into the third SATA header on the motherboard.

Deactivate disk:


**erlangen:~ #** cat /usr/local/bin/delete-backup-disk                                                                            
#!/bin/bash 
if  -f /sys/devices/pci0000:00/0000:00:17.0/ata4/host3/target3:0:0/3:0:0:0/delete ] ; then 
        echo 1 > /sys/devices/pci0000:00/0000:00:17.0/ata4/host3/target3:0:0/3:0:0:0/delete 
fi 
**erlangen:~ #**

Scan for disk:

**erlangen:~ #** cat /usr/local/bin/scan-for-backup-disk  
#!/bin/bash 
echo "- - -" > /sys/devices/pci0000:00/0000:00:17.0/ata4/host3/scsi_host/host3/scan 
**erlangen:~ #**

Services:

Disable HDD on boot and prior to suspend

**erlangen:~ #** systemctl cat HDD-disable.service  
**# /etc/systemd/system/HDD-disable.service**
[Unit] 
Description=Disable backup HDD 

[Service] 
ExecStart=/usr/local/bin/delete-backup-disk 

[Install] 
WantedBy=multi-user.target 
**erlangen:~ #**

Scan for disk:

**erlangen:~ #** systemctl cat HDD-scan.service  
**# /etc/systemd/system/HDD-scan.service**
[Unit] 
Description=Scan for backup HDD 

[Service] 
ExecStart=/usr/local/bin/scan-for-backup-disk 
**erlangen:~ #**

Modification to suspend:

**erlangen:~ #** systemctl cat systemd-suspend 
**# /etc/systemd/system/systemd-suspend.service**
#  SPDX-License-Identifier: LGPL-2.1-or-later 
# 
#  This file is part of systemd. 
# 
#  systemd is free software; you can redistribute it and/or modify it 
#  under the terms of the GNU Lesser General Public License as published by 
#  the Free Software Foundation; either version 2.1 of the License, or 
#  (at your option) any later version. 

[Unit] 
Description=System Suspend 
Documentation=man:systemd-suspend.service(8) 
DefaultDependencies=no 
Requires=sleep.target **HDD-disable.service** 
After=sleep.target **HDD-disable.service** 

[Service] 
Type=oneshot 
ExecStart=/usr/lib/systemd/systemd-sleep suspend 
**erlangen:~ #**

Changes to backup service:

[FONT=monospace]**erlangen:~ #** systemctl cat backup-home.service  
**# /etc/systemd/system/backup-home.service**
[Unit] 
Description=Backup /home 
Requires=HDD.mount **HDD-scan.service** 
After=HDD.mount **HDD-scan.service** 

[Service] 
ExecStart=/usr/bin/rsync -a --exclude=.cache --exclude=covid-19-data /home/ /HDD/backup/home/ 
ExecStopPost=/usr/bin/umount /HDD 
**ExecStopPost=/usr/local/bin/delete-backup-disk **
**erlangen:~ #**

 
[/FONT]

Resume from suspend is now as fast as it was prior to kernel bug:

**erlangen:~ #** journalctl -b -u HDD-disable.service -u systemd-suspend.service --since 11:53 -o short-monotonic              
 4001.282464] erlangen systemd[1]: Started Disable backup HDD. 
 4001.286366] erlangen systemd[1]: Starting System Suspend... 
 4001.289061] erlangen systemd[1]: HDD-disable.service: Deactivated successfully. 
 4001.294992] erlangen systemd-sleep[5105]: INFO: Skip running /usr/lib/systemd/system-sleep/grub2.sleep for suspend 
 **4001.296099**] erlangen systemd-sleep[5103]: Entering sleep state 'suspend'... 
 **4003.592988**] erlangen systemd-sleep[5103]: System returned from sleep state. 
 4003.599700] erlangen systemd-sleep[5119]: INFO: Skip running /usr/lib/systemd/system-sleep/grub2.sleep for suspend 
 4003.600892] erlangen systemd[1]: systemd-suspend.service: Deactivated successfully. 
 4003.601116] erlangen systemd[1]: Finished System Suspend. 
**erlangen:~ #**
2

Few questions;

  • What does mean “deactivated”? Could you fill the table bellow? Change, add or remove info.

                      |State/Mode name|Synonymy|Read/Write|Spinning|Mounted|Power On|Something else|

|—|—|—|—|—|—|—|
|Active|| Y| Y| Y| Y||
|Idle|| N| Y| Y| Y||
|Sleep|||||||
|Standby|| N| N| Y| Y||
|Passive|||||||
|Low power|||||||
|Power off|| N| N|| N||
|Deactivated|| N| N||||

  • Does your new files/settings avoid HDDs to spin-up (if it was spun down) in the process of computer shut down?
3

The disk is physically plugged into the power supply and into the SATA header on the main board. However the system doesn’t know about it. Scanning SATA attaches the drive:

erlangen:~ # ll /dev/sd* 
brw-rw---- 1 root disk 8, 0 Apr  5 20:41 /dev/sda
brw-rw---- 1 root disk 8, 1 Apr  5 20:41 /dev/sda1
erlangen:~ # scan-for-backup-disk  
erlangen:~ # ll /dev/sd*           
brw-rw---- 1 root disk 8,  0 Apr  5 20:41 /dev/sda
brw-rw---- 1 root disk 8,  1 Apr  5 20:41 /dev/sda1
brw-rw---- 1 root disk 8, 16 Apr  6 20:20 /dev/sdb
brw-rw---- 1 root disk 8, 17 Apr  6 20:20 /dev/sdb1
erlangen:~ # hdparm -C /dev/sdb                                                                  

/dev/sdb: 
 drive state is:  active/idle 
erlangen:~ #
4

Order matters:

**erlangen:~ #** systemctl cat backup-home.service                                                                   
**# /etc/systemd/system/backup-home.service**
[Unit] 
Description=Backup /home 
**Requires=HDD-scan.service HDD.mount 
After=HDD-scan.service HDD.mount 
**
[Service] 
ExecStart=/usr/bin/rsync -a --exclude=.cache --exclude=covid-19-data /home/ /HDD/backup/home/ 
ExecStopPost=/usr/bin/umount /HDD 
ExecStopPost=/usr/local/bin/delete-backup-disk 
**erlangen:~ #**

[FONT=monospace]**erlangen:~ #** journalctl -b -u backup-home.service -u 'HDD*' --since 0:00                            
Apr 08 04:49:59 erlangen systemd[1]: Started Scan for backup HDD. 
Apr 08 04:50:10 erlangen systemd[1]: HDD-scan.service: Deactivated successfully. 
Apr 08 04:50:11 erlangen systemd[1]: Mounting /HDD... 
Apr 08 04:50:11 erlangen systemd[1]: Mounted /HDD. 
Apr 08 04:50:11 erlangen systemd[1]: Started Backup /home. 
Apr 08 04:51:40 erlangen systemd[1]: HDD.mount: Deactivated successfully. 
Apr 08 04:51:42 erlangen systemd[1]: backup-home.service: Deactivated successfully. 
Apr 08 04:51:42 erlangen systemd[1]: backup-home.service: Consumed 19.816s CPU time. 
**erlangen:~ #**[/FONT]
5

List activated disks (option N skips nvme):

**erlangen:~ #** lsscsi -sN           
[2:0:0:0]    disk    ATA      CT2000BX500SSD1  030   /dev/sda   2.00TB 
[3:0:0:0]    disk    ATA      WDC WD40EZRX-22S 0A80  /dev/sdb   4.00TB 
[4:0:0:0]    cd/dvd  PIONEER  DVD-RW  DVR-221  1.00  /dev/sr0        - 
**erlangen:~ #**

List device units:

**erlangen:~ #** systemctl list-units --all blockdev@* 
  UNIT                                                                                 LOAD   ACTIVE   SUB  DESCRIPTION                                                                        
  blockdev@dev-disk-by\x2duuid-0e58bbe5\x2deff7\x2d4884\x2dbb5d\x2da0aac3d8a344.target loaded inactive dead Block Device Preparation for /dev/disk/by-uuid/0e58bbe5-eff7-4884-bb5d-a0aac3d8a344 
  blockdev@dev-disk-by\x2duuid-19CF\x2d0B54.target                                     loaded inactive dead Block Device Preparation for /dev/disk/by-uuid/19CF-0B54 
  blockdev@dev-disk-by\x2duuid-5605f149\x2d34a7\x2d4301\x2d9bf3\x2df1f177e35ed6.target loaded inactive dead Block Device Preparation for /dev/disk/by-uuid/5605f149-34a7-4301-9bf3-f1f177e35ed6 
  **blockdev@dev-disk-by\x2duuid-f5177cae\x2d4082\x2d44ed\x2d9471\x2db99030f06866.target** loaded inactive dead Block Device Preparation for /dev/disk/by-uuid/f5177cae-4082-44ed-9471-b99030f06866 
  blockdev@dev-nvme0n1p1.target                                                        loaded inactive dead Block Device Preparation for /dev/nvme0n1p1 
  blockdev@dev-nvme0n1p2.target                                                        loaded inactive dead Block Device Preparation for /dev/nvme0n1p2 
  blockdev@dev-sda1.target                                                             loaded inactive dead Block Device Preparation for /dev/sda1 
  blockdev@dev-sdb1.target                                                             loaded inactive dead Block Device Preparation for /dev/sdb1 

LOAD   = Reflects whether the unit definition was properly loaded. 
ACTIVE = The high-level unit activation state, i.e. generalization of SUB. 
SUB    = The low-level unit activation state, values depend on unit type. 
**8 loaded units listed.**
To show all installed unit files use 'systemctl list-unit-files'. 
**erlangen:~ #**

Change to backup unit:

**erlangen:~ #** systemctl cat backup-home.service               
**# /etc/systemd/system/backup-home.service**
[Unit] 
**erlangen:~ #** systemctl cat backup-home.service                
**# /etc/systemd/system/backup-home.service**
[Unit] 
Description=Backup /home 
Requires=HDD-scan.service HDD.mount 
After=HDD-scan.service **blockdev@dev-disk-by\x2duuid-f5177cae\x2d4082\x2d44ed\x2d9471\x2db99030f06866.target** HDD.mount 

[Service] 
ExecStart=/usr/bin/rsync -a --exclude=.cache --exclude=covid-19-data /home/ /HDD/backup/home/ 
ExecStopPost=/usr/bin/umount /HDD 
ExecStopPost=/usr/local/bin/delete-backup-disk 
**erlangen:~ #**

Dependency on blockdev will cause backup-home.service wait for drive being ready:

**erlangen:~ #** journalctl -b -g sdb                                    
Apr 12 04:58:26 erlangen kernel: **sd 3:0:0:0: ****sdb****] 7814037168 512-byte logical blocks: (4.00 TB/3.64 TiB)**
Apr 12 04:58:26 erlangen kernel: **sd 3:0:0:0: ****sdb****] 4096-byte physical blocks**
Apr 12 04:58:26 erlangen kernel: **sd 3:0:0:0: ****sdb****] Write Protect is off**
Apr 12 04:58:26 erlangen kernel: sd 3:0:0:0: **sdb**] Mode Sense: 00 3a 00 00
Apr 12 04:58:26 erlangen kernel: **sd 3:0:0:0: ****sdb****] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA**
Apr 12 04:58:26 erlangen kernel:  sdb: sdb1 
Apr 12 04:58:26 erlangen kernel: **sd 3:0:0:0: ****sdb****] Attached SCSI disk**
Apr 12 04:58:28 erlangen hd-idle[766]:   disk: sdb timeout: 300 
Apr 12 04:58:28 erlangen kernel: **sd 3:0:0:0: ****sdb****] Synchronizing SCSI cache**
Apr 12 04:58:28 erlangen kernel: **sd 3:0:0:0: ****sdb****] Stopping disk**

Apr 12 06:36:14 erlangen kernel: **sd 3:0:0:0: ****sdb****] 7814037168 512-byte logical blocks: (4.00 TB/3.64 TiB)**
Apr 12 06:36:14 erlangen kernel: **sd 3:0:0:0: ****sdb****] 4096-byte physical blocks**
Apr 12 06:36:14 erlangen kernel: **sd 3:0:0:0: ****sdb****] Write Protect is off**
Apr 12 06:36:14 erlangen kernel: sd 3:0:0:0: **sdb**] Mode Sense: 00 3a 00 00
Apr 12 06:36:14 erlangen kernel: **sd 3:0:0:0: ****sdb****] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA**
Apr 12 06:36:23 erlangen kernel:  sdb: sdb1 
Apr 12 06:36:23 erlangen kernel: **sd 3:0:0:0: ****sdb****] Attached SCSI disk**
Apr 12 06:36:23 erlangen kernel: EXT4-fs (sdb1): mounted filesystem with ordered data mode. Quota mode: none. 
Apr 12 06:38:04 erlangen kernel: **Buffer I/O error on dev ****sdb****1, logical block 1057, async page read**
Apr 12 06:38:04 erlangen kernel: **Buffer I/O error on dev ****sdb****1, logical block 1057, async page read**
Apr 12 06:38:04 erlangen kernel: **sd 3:0:0:0: ****sdb****] Synchronizing SCSI cache**
Apr 12 06:38:04 erlangen kernel: **sd 3:0:0:0: ****sdb****] Stopping disk**
**erlangen:~ #**

**erlangen:~ #** journalctl -b -u backup-home.service -u HDD* 
Apr 12 04:58:28 erlangen systemd[1]: Started Disable backup HDD. 
Apr 12 04:58:29 erlangen systemd[1]: HDD-disable.service: Deactivated successfully. 

Apr 12 06:36:14 erlangen systemd[1]: Started Scan for backup HDD. 
Apr 12 06:36:14 erlangen systemd[1]: HDD-scan.service: Deactivated successfully. 
Apr 12 06:36:23 erlangen systemd[1]: Mounting /HDD... 
Apr 12 06:36:23 erlangen systemd[1]: Mounted /HDD. 
Apr 12 06:36:23 erlangen systemd[1]: Started Backup /home. 
Apr 12 06:38:03 erlangen systemd[1]: HDD.mount: Deactivated successfully. 
Apr 12 06:38:05 erlangen systemd[1]: backup-home.service: Deactivated successfully. 
Apr 12 06:38:05 erlangen systemd[1]: backup-home.service: Consumed 27.369s CPU time. 
**erlangen:~ #**

Deactivation will occur only after successfully unmounting the drive and all data being written. Deactivation of the drive by daily invocation of service backup-home since 31-Mar-2022 left the file system intact:

**erlangen:~ #** fsck.ext4 -f /dev/sdb1 
e2fsck 1.46.5 (30-Dec-2021) 
Pass 1: Checking inodes, blocks, and sizes 
Pass 2: Checking directory structure 
Pass 3: Checking directory connectivity 
Pass 4: Checking reference counts 
Pass 5: Checking group summary information 
HDD: 1557985/244195328 files (0.7% non-contiguous), 576762356/976753920 blocks 
**erlangen:~ # **
6

Waiting for [noparse]blockdev@dev-disk-by\x2duuid-f5177cae\x2d4082\x2d44ed\x2d9471\x2db99030f06866.target[/noparse] doesn’t ensure the disk is ready. Looping until file “delete” shows up in sysfs fixes the issue:

**erlangen:~ #** cat /usr/local/bin/scan-for-backup-disk                
#!/bin/bash  
delete=/sys/devices/pci0000:00/0000:00:01.2/0000:01:00.1/ata5/host4/target4:0:0/4:0:0:0/delete 
scan=/sys/devices/pci0000:00/0000:00:01.2/0000:01:00.1/ata5/host4/scsi_host/host4/scan 
while true ; do 
        echo scanning for backup disk  
         -f $delete ] && exit 
        echo '- - -' > $scan 
done 
**erlangen:~ #**

**Program starter for KDE Plasma:
**

karl@erlangen:~> cat Schreibtisch/Scan\ disk.desktop  
[Desktop Entry] 
Comment[de_DE]= 
Comment= 
Exec=/usr/bin/systemctl start HDD-scan.service 
GenericName[de_DE]= 
GenericName= 
Icon=drive-harddisk-symbolic 
MimeType= 
Name[de_DE]=Scan disk 
Name=Scan disk 
Path= 
StartupNotify=true 
Terminal=false 
TerminalOptions= 
Type=Application 
X-DBUS-ServiceName= 
X-DBUS-StartupType= 
X-KDE-SubstituteUID=false 
X-KDE-Username= 
karl@erlangen:~>

Granting permission:

**erlangen:~ #** cat /etc/polkit-1/rules.d/00-manage-HDD.rules  
// Allow karl to  manage HDD-scan.service; 
// fall back to implicit authorization otherwise. 
polkit.addRule(function(action, subject) { 
    if (action.id == "org.freedesktop.systemd1.manage-units" && 
        action.lookup("unit") == "HDD-scan.service" && 
        subject.user == "karl") { 
        return polkit.Result.YES; 
    } 
}); 
**erlangen:~ #**

**erlangen:~ #** journalctl -b _KERNEL_DEVICE=+scsi:4:0:0:0 --since 08:18 
Booting:
Apr 18 08:18:09 erlangen kernel: **scsi 4:0:0:0: Direct-Access     ATA      ST2000DM001-1CH1 CC29 PQ: 0 ANSI: 5**
Apr 18 08:18:09 erlangen kernel: **sd 4:0:0:0: Attached scsi generic sg2 type 0**
Apr 18 08:18:16 erlangen kernel: **sd 4:0:0:0: [sdc] 3907029168 512-byte logical blocks: (2.00 TB/1.82 TiB)**
Apr 18 08:18:16 erlangen kernel: **sd 4:0:0:0: [sdc] 4096-byte physical blocks**
Apr 18 08:18:16 erlangen kernel: **sd 4:0:0:0: [sdc] Write Protect is off**
Apr 18 08:18:16 erlangen kernel: sd 4:0:0:0: [sdc] Mode Sense: 00 3a 00 00
Apr 18 08:18:16 erlangen kernel: **sd 4:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA**
Apr 18 08:18:16 erlangen kernel: **sd 4:0:0:0: [sdc] Attached SCSI disk**
Apr 18 08:18:49 erlangen kernel: **sd 4:0:0:0: [sdc] Synchronizing SCSI cache**
Apr 18 08:18:49 erlangen kernel: **sd 4:0:0:0: [sdc] Stopping disk**
Scanning:
Apr 18 09:00:59 erlangen kernel: **scsi 4:0:0:0: Direct-Access     ATA      ST2000DM001-1CH1 CC29 PQ: 0 ANSI: 5**
Apr 18 09:01:05 erlangen kernel: **sd 4:0:0:0: Attached scsi generic sg2 type 0**
Apr 18 09:01:06 erlangen kernel: **sd 4:0:0:0: [sdc] 3907029168 512-byte logical blocks: (2.00 TB/1.82 TiB)**
Apr 18 09:01:06 erlangen kernel: **sd 4:0:0:0: [sdc] 4096-byte physical blocks**
Apr 18 09:01:06 erlangen kernel: **sd 4:0:0:0: [sdc] Write Protect is off**
Apr 18 09:01:06 erlangen kernel: sd 4:0:0:0: [sdc] Mode Sense: 00 3a 00 00
Apr 18 09:01:06 erlangen kernel: **sd 4:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA**
Apr 18 09:01:06 erlangen kernel: **sd 4:0:0:0: [sdc] Attached SCSI disk**
Disabling:
Apr 18 09:01:07 erlangen kernel: **sd 4:0:0:0: [sdc] Synchronizing SCSI cache**
Apr 18 09:01:07 erlangen kernel: **sd 4:0:0:0: [sdc] Stopping disk**
**erlangen:~ #**
7

Further testing revealed that dealing with systemd ordering is cumbersome and spurious failures occur. Revised scripts have mounting and unmounting the drive included:

**erlangen:~ #** cat /usr/local/bin/scan-for-backup-disk                                           
#!/bin/bash  
echo "- - -" > /sys/devices/pci0000:00/0000:00:01.2/0000:04:00.1/ata1/host0/scsi_host/host0/scan 
until  -d /HDD/backup ] ; do echo Scanning backup disk ; sleep 1; done 
**erlangen:~ #** cat /usr/local/bin/disable-backup-disk                                           
#!/bin/bash 
delete=/sys/devices/pci0000:00/0000:00:01.2/0000:04:00.1/ata1/host0/target0:0:0/0:0:0:0/delete 
 -d /HDD/backup ] && umount /HDD || true 
 -f $delete ] && echo 1 > $delete || true 
**erlangen:~ #**
8

In the scripts you test the sub-directory /HDD/backup. In the case you change the name of this sub-directory the scripts will fail.
As my HDD is ext4 formatted, is it possible to use the sub-directory /lost+found instead?

9

This will work presumably. But it may create lots of confusion. Don’t do that. Create a mount point of your own liking.

10

Revised script relied on mounting as a side effect, which no longer occurs with kernel 5.18:

New version explicitly mounts the device:

**erlangen:~ #** cat /usr/local/bin/scan-for-backup-disk             
#!/bin/bash  
echo "- - -" > /sys/devices/pci0000:00/0000:00:01.2/0000:04:00.1/ata1/host0/scsi_host/host0/scan 
until  -L /dev/disk/by-uuid/f5177cae-4082-44ed-9471-b99030f06866 ] ; do echo Scanning backup disk ; sleep 1; done 
 -d /HDD/backup ] || mount /HDD || true 
**erlangen:~ #**
11

Hide partitions from udisks:

**erlangen:~ #** cat /etc/udev/rules.d/10-local.rules                       
SUBSYSTEM=="block", ENV{ID_FS_UUID}=="2260f160-cc05-47cc-9893-cc32c050177d", ENV{UDISKS_IGNORE}="1" 
SUBSYSTEM=="block", ENV{ID_FS_UUID}=="f5177cae-4082-44ed-9471-b99030f06866", ENV{UDISKS_IGNORE}="1" 
**erlangen:~ #**

https://wiki.archlinux.org/title/Udisks#Hide_selected_partitions