How do I find out what hard disks are in the system?

Question

I need to know what hard disks are available, including ones that aren't mounted and possibly aren't formatted. I can't find them in dmesg or /var/log/messages (too much to scroll through). I'm hoping there's a way to use /dev or /proc to find out this information, but I don't know how. I am using Linux.

Answer 1

This is highly platform-dependent. Also different methods may treat edge cases differently (“fake” disks of various kinds, RAID volumes, …).

On modern udev installations, there are symbolic links to storage media in subdirectories of /dev/disk, that let you look up a disk or a partition by serial number (/dev/disk/by-id/), by UUID (/dev/disk/by-uuid), by filesystem label (/dev/disk/by-label/) or by hardware connectivity (/dev/disk/by-path/).

Under Linux 2.6, each disk and disk-like device has an entry undr /sys/block. Under Linux since the dawn of time, disks and partitions are listed in /proc/partitions. Alternatively, you can use lshw: lshw -class disk.

If you have an fdisk or disklabel utility, it might be able to tell you what devices it's able to work on.

You will find utility names for many unix variants on the Rosetta Stone for Unix, in particular the “list hardware configuration” and “read a disk label” lines.

Answer 2

How about

lshw -class disk

Answer 3

@Giles says this is highly platform-dependent. Here's one such example.

I'm running a CentOS 5.5 system. This system has 4 disks and a 3ware RAID controller.

In my case, lshw -class disk, cat /proc/scsi/scsi and parted --list shows the RAID controller (3ware 9650SE-4LP). This doesn't show the actual disks:

only shows the 3ware RAID controller which provides the /dev/sda volume:

# lshw -class disk
  *-disk                  
       description: SCSI Disk
       product: 9650SE-4LP DISK
       vendor: AMCC
       physical id: 0.0.0
       bus info: scsi@0:0.0.0
       logical name: /dev/sda

# cat /proc/scsi/scsi 
Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
  Vendor: AMCC     Model: 9650SE-4LP DISK  Rev: 4.06
  Type:   Direct-Access                    ANSI SCSI revision: 05

# parted --list

Model: AMCC 9650SE-4LP DISK (scsi)
Disk /dev/sda: 2000GB

In order to see the disks which lie underneath, I had to install the tw_cli utility from 3ware, and ask the controller itself.

# tw_cli info c0
...

VPort Status         Unit Size      Type  Phy Encl-Slot    Model
------------------------------------------------------------------------------
p0    OK             u0   931.51 GB SATA  0   -            WDC WD1002FBYS-02A6 
p1    OK             u0   931.51 GB SATA  1   -            WDC WD1002FBYS-02A6 

Answer 4

hwinfo helps:

> hwinfo --disk
21: IDE 00.0: 10600 Disk                                        
[Created at block.245]
Unique ID: 3OOL.8MZXfAWnuH8
Parent ID: w7Y8.1T_0outZkp6
SysFS ID: /class/block/sda
SysFS BusID: 0:0:0:0
SysFS Device Link: /devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0
Hardware Class: disk
Model: "Hitachi HTS54322"
Vendor: "Hitachi"
Device: "HTS54322"
Revision: "ESBO"
Driver: "ahci", "sd"
Driver Modules: "ahci"
Device File: /dev/sda
Device Files: /dev/sda, /dev/disk/by-id/ata-Hitachi_HTS543225A7A384_E2021342GEPG4J, /dev/disk/by-id/scsi-SATA_Hitachi_HTS5432_E2021342GEPG4J, /dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0, /dev/disk/by-id/wwn-0x5000cca614c6395e
Device Number: block 8:0-8:15
BIOS id: 0x80
Geometry (BIOS EDD): CHS 484521/16/63
Size (BIOS EDD): 488397168 sectors
Geometry (BIOS Legacy): CHS 1023/255/63
Drive status: no medium
Config Status: cfg=new, avail=yes, need=no, active=unknown
Attached to: #17 (SATA controller)
> hwinfo --block --short
disk:                                                           
  /dev/sda             Hitachi HTS54322
partition:
  /dev/sda1            Partition
  /dev/sda2            Partition
  /dev/sda3            Partition
  /dev/sda4            Partition
  /dev/sda5            Partition

Answer 5

I'm running fedora 14 and lshw is not available here (at least not by default). However in my case, I used fdisk -l command (as a root user) to get the following output:

Disk /dev/sda: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders, total 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0006a697

Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     1026047      512000   83  Linux
/dev/sda2         1026048    16777215     7875584   8e  Linux LVM

Disk /dev/sdb: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders, total 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdb doesn't contain a valid partition table

Disk /dev/dm-0: 6509 MB, 6509559808 bytes
255 heads, 63 sectors/track, 791 cylinders, total 12713984 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/dm-0 doesn't contain a valid partition table

Disk /dev/dm-1: 1543 MB, 1543503872 bytes
255 heads, 63 sectors/track, 187 cylinders, total 3014656 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/dm-1 doesn't contain a valid partition table

Answer 6

lshw is provided by lshw-* package.

yum install lshw* 

Running above command as a root will install the package.

lshw -class disk will work now.

Answer 7

This worked for me:

fdisk -l 2>/dev/null | grep "Disk \/" | grep -v "\/dev\/md" | awk '{print $2}' | sed -e 's/://g'