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Test the write speed of your devices using dd


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#1 Al1000

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Posted 25 July 2016 - 09:43 AM

Warning: Be very careful using the dd command. If you tell it to overwrite something, such as your home directory, that's what it will do, without any further prompts or warnings.

Running this command will write 2.1GB of data to a file called output.img in your /tmp directory
 
dd if=/dev/zero of=/tmp/output.img bs=8k count=256k conv=fdatasync
Adding conv=fdatasync at the end, ensures that results will not be reported before writing is completed.

Here are the results from Kubuntu 14.04 on my WD black 1TB SATA HDD:

al@my-desktop-pc:~$ dd if=/dev/zero of=/tmp/output.img bs=8k count=256k conv=fdatasync
262144+0 records in
262144+0 records out
2147483648 bytes (2.1 GB) copied, 13.0061 s, 165 MB/s

When finished, you can delete the 2.1GB file by running this command:
rm /tmp/output.img

To test the write speed of a USB drive, first of all I'll create a directory called /tmp on the drive:
mkdir /media/al/USB_3/tmp
Then write 2.1GB of data to that directory:
dd if=/dev/zero of=/media/al/USB_3/tmp/output.img bs=8k count=256k conv=fdatasync
This is a USB 3.0 drive, in a USB 2.0 port. Here are the results:

al@my-desktop-pc:~$ dd if=/dev/zero of=/media/al/USB_3/tmp/output.img bs=8k count=256k conv=fdatasync
262144+0 records in
262144+0 records out
2147483648 bytes (2.1 GB) copied, 794.273 s, 2.7 MB/s

Edited by Al1000, 25 July 2016 - 09:44 AM.


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#2 Al1000

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Posted 25 July 2016 - 09:57 AM

Here are the results from the 40GB IDE HDD on my old PB EasyNote E6307 laptop:

$ dd if=/dev/zero of=/tmp/output.img bs=8k count=256k conv=fdatasync
262144+0 records in
262144+0 records out
2147483648 bytes (2.1 GB) copied, 85.4669 s, 25.1 MB/s

#3 Al1000

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Posted 25 July 2016 - 11:29 AM

Back on Kubuntu 14.04, here's the results of writing to my WD Green 1TB HDD:

al@my-desktop-pc:~$ dd if=/dev/zero of=/media/al/Storage/tmp/output.img bs=8k count=256k conv=fdatasync
262144+0 records in
262144+0 records out
2147483648 bytes (2.1 GB) copied, 16.3882 s, 131 MB/s

I'd be interested in what speeds Linux users with SSDs can get.

#4 Condobloke

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Posted 25 July 2016 - 07:58 PM

On Linux Mint Sarah (18, Cinnamon)...

 

brian@brian-desktop ~ $ dd if=/dev/zero of=/tmp/output.img bs=8k count=256k conv=fdatasync
262144+0 records in
262144+0 records out
2147483648 bytes (2.1 GB, 2.0 GiB) copied, 4.93535 s, 435 MB/s
brian@brian-desktop ~ $

 

Edit:..Samsung 120GB SSD
 


Edited by Condobloke, 25 July 2016 - 08:00 PM.

Condobloke ...Outback Australian  fed up with Windows antics...??....LINUX IS THE ANSWER....I USE LINUX MINT 18.3  EXCLUSIVELY.

“A man travels the world in search of what he needs and returns home to find it."

It has been said that time heals all wounds. I don't agree. The wounds remain. Time - the mind, protecting its sanity - covers them with some scar tissue and the pain lessens, but it is never gone. Rose Kennedy

 GcnI1aH.jpg

 

 


#5 NickAu

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Posted 25 July 2016 - 08:24 PM

nick@Sith:~$ dd if=/dev/zero of=/tmp/output.img bs=8k count=256k conv=fdatasync
262144+0 records in
262144+0 records out
2147483648 bytes (2.1 GB) copied, 5.08397 s, 422 MB/s

 

Sandisk 256 gb SSD
 


Edited by NickAu, 25 July 2016 - 08:36 PM.


#6 Al1000

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Posted 26 July 2016 - 05:51 AM

Thanks guys. Your SSDs are not as fast as I thought they would be. :)

#7 NickAu

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Posted 26 July 2016 - 06:02 AM

These are Sandisk's claimed read and write speeds

 

Capacity: 240 GB.
Read Speed: up to 550 MB/s.
Write Speed: up to 500 MB/s.
Interface: SATA Revision 3.0 (6 Gb/s)

Not that far off?



#8 Al1000

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Posted 26 July 2016 - 06:12 AM

That seems reasonably close.

I just looked up the write speed for my WD black 1TB HDD and it's 150MB/s, so at 165MB/s I would seem to be exceeding it.

http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771434.pdf

#9 NickAu

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Posted 26 July 2016 - 06:18 AM

Remember most manufacturers will claim the fastest write speeds they can, even if that write speed was a blip that lasts a milli second, Kinda like ISP's say you get xxx download speed, or Like when speaker manufacturers say 1000 wats then in small letters say PMPO instead of RMS.

 

PMPO is a controversy term, as many feel it is used as a marketing ploy, since the perfect conditions on which PMPO are based are next to impossible to achieve in a home where the speaker system is set up. The PMPO of a speaker is actually based on the maximum power output in a very small period of time (microseconds)


Edited by NickAu, 26 July 2016 - 06:18 AM.


#10 Al1000

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Posted 26 July 2016 - 06:42 AM

I recall always looking for (or approximately calculating) the Root Mean Square power output of speakers, rather than the claimed "maximum" output.

/off-topic. :)

#11 TsVk!

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Posted 26 July 2016 - 04:23 PM

Seems like mine is running slow for some reason, considering it is a 1TB Samsung 850 Pro on Debian Jessie.

 

TSLGROUP+jmccormack@mispc4-deb:~$ dd if=/dev/zero of=/tmp/output.img bs=8k count=256k conv=fdatasync
262144+0 records in
262144+0 records out
2147483648 bytes (2.1 GB) copied, 8.57602 s, 250 MB/s

 

Will have to look into this.
 


Edited by TsVk!, 26 July 2016 - 04:28 PM.


#12 TsVk!

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Posted 26 July 2016 - 04:37 PM

Was just checking out my read speeds with hdparm.

 

root@mispc4-deb:/home/TSLGROUP/jmccormack# hdparm -Tt /dev/sda

/dev/sda:
 Timing cached reads:   27386 MB in  2.00 seconds = 13706.70 MB/sec
 Timing buffered disk reads: 806 MB in  3.01 seconds = 268.07 MB/sec
 

Slightly disconcerting really.



#13 Al1000

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Posted 26 July 2016 - 04:57 PM

Interesting. Your "timing cache reads" are around 11x as fast as my WD 1TB black HDD, but the "timing buffered disk reads" are less than twice as fast.

 

al@my-desktop-pc:~$ sudo hdparm -Tt /dev/sda

/dev/sda:
 Timing cached reads:   2390 MB in  2.00 seconds = 1196.13 MB/sec
 Timing buffered disk reads: 556 MB in  3.01 seconds = 184.67 MB/sec



#14 TsVk!

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Posted 26 July 2016 - 05:02 PM

Yeah, there's some sort of issue... more stuff to fix. Lol.



#15 NickAu

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Posted 26 July 2016 - 05:16 PM

Timing cached reads:   25816 MB in  2.00 seconds = 12921.94 MB/sec
 Timing buffered disk reads: 1546 MB in  3.00 seconds = 514.95 MB/sec
 






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