How to know if a disk is an SSD or an HDD

Question

I want to know whether a disk is a solid-state drive or hard disk.

lshw is not installed. I do yum install lshw and it says there is no package named lshw. I do not know which version of http://pkgs.repoforge.org/lshw/ is suitable for my CentOS.

I search the net and there is nothing that explain how to know whether a drive is SSD or HDD. Should I just format them first?

Result of fdisk -l:

Disk /dev/sda: 120.0 GB, 120034123776 bytes
255 heads, 63 sectors/track, 14593 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00074f7d

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          14      103424   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              14         536     4194304   82  Linux swap / Solaris
Partition 2 does not end on cylinder boundary.
/dev/sda3             536       14594   112921600   83  Linux

Disk /dev/sdc: 120.0 GB, 120034123776 bytes
255 heads, 63 sectors/track, 14593 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000


Disk /dev/sdb: 128.0 GB, 128035676160 bytes
255 heads, 63 sectors/track, 15566 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000


Disk /dev/sdd: 480.1 GB, 480103981056 bytes
255 heads, 63 sectors/track, 58369 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Solution 1

Linux automatically detects SSD, and since kernel version 2.6.29, you may verify sda with:

cat /sys/block/sda/queue/rotational

You should get 1 for hard disks and 0 for a SSD.

It will probably not work if your disk is a logical device emulated by hardware (like a RAID controller).

See this answer for more information about SSD partitioning, filesystem...

Solution 2

With lsblk (part of the util-linux package):

lsblk -d -o name,rota

NAME ROTA
sda     0
sdb     0
sdc     1

where ROTA means rotational device (1 if true, 0 if false)

Solution 3

Use smartctl (install by installing smartmontools) to retrieve vendor information,

sudo smartctl -a /dev/sdb

If you see a line like this,

Rotation Rate: Solid State Device

That would be a SSD drive.

Solution 4

I needed to do this on the VPS and none of the provided solutions worked for me, but this answer did the trick:

https://serverfault.com/questions/551453/how-do-i-verify-that-my-hosting-provider-gave-me-ssds/551495#551495

This just reads random data from the drive and assesses the time.

time for i in `seq 1 1000`; do
    dd bs=4k if=/dev/sda count=1 skip=$(( $RANDOM * 128 )) >/dev/null 2>&1;
done

NOTE: You may need sudo before the dd command, depending on your permissions.

Here are my results for an SSD:

real    0m1.375s
user    0m0.285s
sys     0m0.944s

And a HDD:

real    0m14.249s
user    0m0.752s
sys     0m6.284s

As you can see, the HDD takes about 10x the duration. This may not be reliable for some very fast HDD's, but in general, it will give you a good idea.

Solution 5

The other answers already tell you how to get this information in a number of ways , including /proc. But you must expect all these mechanisms to lie if there's any virtualisation in the way, such as a hybrid SAN array with multiple tiers, or if the Linux machine is a virtual machine (where Linux will probably report the disk as a basic SCSI rotating disk, regardless of what the hardware really is)

View more solutions

Comments

[phuclv]

How to check if my Ubuntu is placed on SSD?

[Matt]

dmesg will contain the same info. dmesg | grep -i -e scsi -e ata

[PythoNic]

On Stackoverflow somebody found this sys-info didn't work.

[Totor]

@PythoNic please file a kernel bug report about this.

[PythoNic]

@totor Better add this comment on the other post. I don't know his/her kernel version :)

[haridsv]

Nice! Works without having sudo privileges.

[dma_k]

The method does not work for USB sticks – they are certainly not rotational drives (see Doesn't detect USB flash drive as SSD).

[dma_k]

That utility seems to report the same information as in /sys/block/.../rotational.

[CMCDragonkai]

What about hybrid drives?

[Totor]

@CMCDragonkai They propably appear as rotational since the flash memory is mostly an "improved cache". You tell us...

[the_nuts]

I have a non-ssd, RAID10, and my results are: real 0m1.351s - user: 0m0.307s - sys: 0m0.560s

[user]

@dma_k Little wonder, considering it appears to use that one. Try it yourself: strace lsblk -d -o name,rota /dev/sda 2>&1 | grep --context=3 --color rotational

[dma_k]

Actually I was looking into various ways because some USB controllers don't tell that drive is actually non-rotational (for example, USB flash) and there is no way in Linux to tell the truth. At the end of the day I have fixed that by creating the explicit rule in /etc/udev/rules.d/90-non-rotational.rules: ACTION=="add|change", SUBSYSTEMS=="usb", ENV{ID_SERIAL}=="SanDisk_Ultra_Fit_*-0:0", ATTR{queue/rotational}="0", ATTR{queue/scheduler}="deadline"

[itoctopus]

This is a good answer and it does work across the board. The thing is some HDDs are quite fast and the results can be similar to those of SSDs. Still, this answer provides a good metric.

[Terrance]

@Totor You are correct in the "hybrid" drives. However, dual-drive hybrids show up as two individual drives, where SSHD (Solid-State Hybrid Drive) shows up as a single drive. So, the SSHD would show rotational of 1.

[Alessio]

+1. nice, but running that on my (aging and soon to be replaced) WD Greens says Medium rotation rate is not reported. hdparm and smartmonctl say the same. I guess WD don't want to tell.

[trr]

On my VPS without an SSD this provides results like your SSD example. I believe this may be fooled by "hybrid" (SSD cached HDD) setups.

[tuk0z]

lsblk reports "0" for all my good old SATA spinning HDDs here (ASROCK mobo). « some USB controllers don't tell that drive is actually non-rotational (for example, USB flash) » @dma_k this is so true --and better this way than the other way for USB wired external spinning HDDs IMHA.

[user2241406]

On virtual servers, you may need to fetch /sys/block/vda/queue/rotational

[ron]

this may be one of the more important responses... and also within the BIOS, or EFI/UEFI one may need to set the SATA controller mode to AHCI and then also mark each disk as SSD within the bios. My Asrock board on home pc is like this, can't remember if there was a similiar thing on server boards (supermicro) I have at work but i don't use SSD at work.

[Toby]

doesn't work for me. I find SSD and HDD produce similar result.

[Ferrybig]

On certain computers, you need to run cat /sys/block/nvme0n1/queue/rotational instead, sda does not exist on my laptop

[Motivated]

@ron - What do you mean by setting the SATA controller mode to AHCI? How does it affect the ability to accurately report if the device is a SSD or not?

[ron]

look up AHCI vs IDE, wording from first web search: IDE is considered adequate for the average computer user, and is the most compatible with other technology, particularly older devices. However, it lacks support for new technologies...AHCI provides a standard system that designers and developers can use to configure, detect, or program SATA/AHCI adapters.*

[ron]

that is a basic settings in the BIOS, somewhere under Storage, the choices are IDE, AHCI, and also depending on make/model/year of motherboard can also offer RAID. SSD's came out long after IDE basically went obsolete and the standard became AHCI, For example installing Windows95 on a computer today it would not recognize any hardware... being in IDE mode certainly would not help communication with a SSD not so much accuracy but simply being able to communicate with a SATA controller which is based on AHCI protocols.

[vidarlo]

On a VPS hardware's virtualized. You can't really tell if your files are stored on a HDD, cached, or stored on a SSD.

[Marki555]

@Ferrybig There are only SSDs in NVME format, not HDDs (unless you do have some strange breakout adapter from NVME slot to plain SATA cable). But not sure if even SATA SSD over NVME shows as NVME in linux or as plain sdX.

[crysman]

this one is better than unix.stackexchange.com/posts/65602/revisions because it lists all devices

[arielf]

This seems to show only ATA/SCSI block-devices, others such as NVMe SSDs do not show.

[arielf]

This works best for me, but it includes redundant/unwanted loop devices (e.g. due to Ubuntu snaps). A slight improvement is: lsblk -d -e 7 -o NAME,ROTA,DISC-MAX,MODEL which excludes loop devices + adds the model name (manufacturer) and disk capacity.

[arielf]

This works if you know which device to show (e.g. sda) a-priori. If you want to discover disks + whether they are rotational, try @don_crissti answer.

[user515185]

ajouté | grep -v 'loop' dans la commande pour ignorer les "block device" virtuel ex: for SsDrive in $(find /sys/block/* -maxdepth 1 -exec echo {} \; -exec grep '0' {}/queue/rotational \; | grep -v 'loop' | grep -B1 '^0' | grep '^/' | sed 's/^.*\///g') ; do find /dev/ -name $SsDrive[0-9] ; done

[ron]

if your disk is behind a raid controller, you will only see the raid controller such as Vendor: LSI Model: SMC3108 Rev: 4.27

[Jeff Schaller]

I noticed after my translation yesterday that you've previously rolled back attempted translations. Please note that answers on this site should be in English. Thank you!

[user515185]

Add | grep -v 'loop' on the command line to forget the loop (virtual block device ) ex: for SsDrive in $(find /sys/block/* -maxdepth 1 -exec echo {} \; -exec grep '0' {}/queue/rotational \; | grep -v 'loop' | grep -B1 '^0' | grep '^/' | sed 's/^.*\///g') ; do find /dev/ -name $SsDrive[0-9] ; done

[spacebiker]

This didn't work for me, both the hd and the ssd show 1

[gavv]

Description does not always include "HDD" or "SSD".

[Admin]

This work for me, i got 0, my disk is SSD.