Introduction

This Python library can assist in collecting disk information on Linux. In more details, it can:

• collect information about a specific disk

• explore all existing disks in the system

• translate between traditional and persistent disk names

• read disk temperature

• read SMART attributes of a disk

• read partition list of a disk

Installation

Standard installation from pypi:

pip install diskinfo

The library has the following run-time requirements:

• Python version >= 3.8

• for reading SMART data with get_smart_data() method, the smartmontools package is required

• for reading disk temperature with get_temperature() method, the following dependencies needs to be considered:

  Disk type	Requirement
  SATA HDD/SSD	drivetemp kernel module (Linux kernel version 5.6+) has to be loaded
  SCSI/ATA HDD	smartmontools has to be installed
  NVME	none

• for reading disk partition information with get_partition_list() method, the df command is required.

• optionally, for the demo Rich Python library is required

Demo

The library contains a demo application with multiple screens. In order to run demo execute the following commands:

pip install rich

The first demo screen will list the explored disks:

python -m diskinfo.demo

The second demo screen will display the attributes of a specified disk:

python -m diskinfo.demo sdb

The third demo screen will display the SMART attributes of a specified disk:

python -m diskinfo.demo nvme0n1 -s

The fourth demo screen will display the list of partitions on a specified disk:

python -m diskinfo.demo nvme0n1 -p

Persistent disk names

Please note that the traditional disk names in Linux are not persistent:

/dev/sda
/dev/sdb

It means they can refer a different physical disk after a reboot. Read more about this topic at Arch Linux wiki: Persistent block device naming.

On the other hand, there are real persistent ways to refer disk or block devices in Linux:

1. by-id path: it can be found in /dev/disk/by-id directory and it is constructed with disk serial numbers:

   /dev/disk/by-id/ata-Samsung_SSD_850_PRO_1TB_92837A469FF876
   /dev/disk/by-id/wwn-0x5002539c417223be
   

2. by-path path: it can be found in /dev/disk/by-path directory and it is constructed with a physical path to the disk:

   /dev/disk/by-path/pci-0000:00:17.0-ata-3
   

There are similar persistent constructions for disk partitions, too.

How to use

The following chapters will present the six use cases listed in the Introduction chapter above.

Use case 1: collect information about a disk

Disk attributes can be collected with the creation of a Disk class. All disk attributes will be collected at class creation time:

>>> from diskinfo import Disk
>>> d = Disk("sda")

and later the attributes can be accessed with the help of get functions of the class:

>>> d.get_model()
'Samsung SSD 870 QVO 8TB'
>>> d.is_ssd()
True
>>> s, u = d.get_size_in_hrf()
>>> print(f"{s:.1f} {u}")
8.0 TB
>>> d.get_serial()
'S5SXNG0MB01829M'

The Disk class contains the following disk attributes:

Attribute	Description	Sample value
name	Disk name	sda or nvme0n1)
path	Disk path	/dev/sda or /dev/nvme0n1
by-id path	Persistent disk path in /dev/disk/by-id directory
by-path path	Persistent disk path in /dev/disk/by-path directory
wwn	World Wide Name	0x5002538c307370ec
model	Disk model	Samsung SSD 850 PRO 1TB
serial number	Disk serial number	S3E2NY0J723218R
firmware	Disk firmware	EXM04B6Q
type	Disk type	HDD, SSD or NVME
size	Disk size in 512-byte blocks
device id	Disk device id, in ‘major:minor’ form	8:0
physical block size	Disk physical block size in bytes	512 or 4096
logical block size	Disk logical block size in bytes	512
partition table type	Type of the partition table on disk	gpt or mbr
partition table uuid	UUID of the partition table on disk

Use case 2: explore disks

Disks can be explored with the creation of the DiskInfo class. During this process all disks will identified and their attributes will be stored:

>>> from diskinfo import Disk, DiskInfo
>>> di = DiskInfo()

After that, the number of identified disks can be read with the help of get_disk_number() method:

>>> di.get_disk_number()
4

and the list of the disks can be accessed (see more details in get_disk_list() method):

>>> disks = di.get_disk_list(sorting=True)
>>> for d in disks:
>>>     print(d.get_path())
/dev/nvme0n1
/dev/sda
/dev/sdb
/dev/sdc

The caller can also apply filters (i.e. included and excluded disk types) for both functions and can query only subset of the disks based on one or more specific DiskType. The list of disk can be also sorted.

Use case 3: translate between traditional and persistent disk names

Translation from traditional disk names to persistent ones can be done this way:

>>> from diskinfo import Disk
>>> d = Disk("sda")
>>> d.get_byid_path()
['/dev/disk/by-id/ata-Samsung_SSD_850_PRO_1TB_92837A469FF876', '/dev/disk/by-id/wwn-0x5002539c417223be']
>>> d.get_bypath_path()
['/dev/disk/by-path/pci-0000:00:17.0-ata-3', '/dev/disk/by-path/pci-0000:00:17.0-ata-3.0']
>>> d.get_serial_numner()
'92837A469FF876'
>>> d.get_wwn()
'0x5002539c417223be'

In the opposite direction several unique (persistent) identifier can be used to initialize Disk class then the traditional disk path or name can be read:

>>> from diskinfo import Disk
>>> d = Disk(byid_name="ata-Samsung_SSD_850_PRO_1TB_92837A469FF876")
>>> d.get_path()
'/dev/sda'
>>> d = Disk(bypath_name="pci-0000:00:17.0-ata-3")
>>> d.get_path()
'/dev/sda'
>>> d = Disk(serial_number="92837A469FF876")
>>> d.get_path()
'/dev/sda'
>>> d = Disk(wwn="0x5002539c417223be")
>>> d.get_name()
'sda'

Use case 4: read disk temperature

After having a Disk class instance, the disk temperature can be read in this way:

>>> from diskinfo import Disk
>>> d = Disk("sda")
>>> d.get_temperature()
28

Please note that the drivetemp kernel module should be loaded for SSDs and HDDs (available from Linux Kernel 5.6+). NVME disks do not require anything.

Use case 5: read disk SMART attributes

After having a Disk class instance, the SMART attributes of the disk can be read with the help of get_smart_data() method.

>>> from diskinfo import Disk, DiskSmartData
>>> d = Disk("sda")
>>> sd = d.get_smart_data()

In case of HDDs, we can skip checking if they are in STANDBY mode:

>>> sd = d.get_smart_data(nocheck=True)
>>> if sd.standby_mode:
...     print("Disk is in STANDBY mode.")
... else:
...     print("Disk is ACTIVE.")
...
Disk is in STANDBY mode.

If we dont use the nocheck parameter here (when the HDD is in STANDBY mode) then the HDD will spin up and will return to ACTIVE mode. Please note if standby_mode is True then no other SMART attributes are loaded.

The most important SMART information for all disk types is the health status:

>>> if sd.healthy:
...     print("Disk is HEALTHY.")
... else:
...     print("Disk is FAILED!")
...
Disk is HEALTHY.

In case of SSDs and HDDs the traditional SMART attributes can be accessed via smart_attributes list:

>>> for item in sd.smart_attributes:
...     print(f"{item.id:>3d} {item.attribute_name}: {item.raw_value}")
...
  5 Reallocated_Sector_Ct: 0
  9 Power_On_Hours: 6356
 12 Power_Cycle_Count: 2308
177 Wear_Leveling_Count: 2
179 Used_Rsvd_Blk_Cnt_Tot: 0
181 Program_Fail_Cnt_Total: 0
182 Erase_Fail_Count_Total: 0
183 Runtime_Bad_Block: 0
187 Uncorrectable_Error_Cnt: 0
190 Airflow_Temperature_Cel: 28
195 ECC_Error_Rate: 0
199 CRC_Error_Count: 0
235 POR_Recovery_Count: 67
241 Total_LBAs_Written: 9869978356

See more details in DiskSmartData and SmartAttribute classes.

In case of NVME disks they have their own SMART data in nvme_attributes attribute:

>>> if d.is_nvme():
...     print(f"Power on hours: {sd.nvme_attributes.power_on_hours} h")
...
Power on hours: 1565 h

See the detailed list of the NVME attributes in NvmeAttributes class.

Please note that the get_smart_data() method relies on smartctl command. It means that the caller needs to have special access rights (i.e. sudo or root).

Use case 6: read partition list

After having a Disk class instance, the partition list can be read with the help of get_partition_list() method.

>>> from diskinfo import Disk, DiskSmartData
>>> d = Disk("sda")
>>> plist = d.get_partition_list()

The return value is a list of Partition classes. This class provides several get functions to access the partition attributes:

>>> from diskinfo import Disk
>>> disk = Disk("nvme0n1")
>>> plist = disk.get_partition_list()
>>> for item in plist:
...     Disk(item.get_name())
...
nvme0n1p1
nvme0n1p2
nvme0n1p3
nvme0n1p4
nvme0n1p5
nvme0n1p6

The Partition class contains the following partition attributes:

Attribute	Description	Sample value
name	Partition name	sda1 or nvme0n1p1
Path	Partition path	/dev/sda1 or /dev/nvme0n1p1
by-id path	Persistent path in /dev/disk/by-id directory
by-path path	Persistent path in /dev/disk/by-path directory
by-partuuid path	Persistent path in /dev/disk/by-partuuid directory
by-partlabel path	Persistent path in /dev/disk/by-partlabel directory
by-uuid path	Persistent path in /dev/disk/by-uuid directory
by-label path	Persistent path in /dev/disk/by-label directory
Device id	Partition device id	8:1
Partition scheme	Partition scheme	gtp or mbr
Partition label	Partition label	Basic data partition
Partition UUID	Partition UUID	acb8374d-fb60-4cb0-8ac4-273417c6f847
Partition type	Partition type UUID
Partition number	Partition number in the partition table
Partition offset	Partition starting offset in 512-byte blocks
Partition size	Partition size in 512-byte blocks
File system label	File system label
File system UUID	File system UUID
File system type	File system type	ntfs or ext4)
File system version	File system version	1.0 in case of ext4)
File system usage	File system usage	filesystem or other
File system free size	File system free size in 512-byte blocks
File system mounting point	File system mounting point	/ or /home