system response issue

[jd1008]

On 07/13/2015 03:13 PM, Patrick O'Callaghan wrote:
> On Mon, 2015-07-13 at 13:50 -0600, jd1008 wrote:
>> I started a tar command from
>> one external eSATA drive (ext4), connected to eSATA port,
>> out to a USB flash drive (with vfat). The USB stick is touted
>> to support 50MB/s write, 160MB/s read.
> Have you actually measured its real write speed for large files? Try
> something like:
>
> time dd if=/dev/zero of=/the/usb/drive count=1000 bs=1M
>
> You might be surprised.
>
> poc
Well, I am not surprised, but disappointed (seriously!!!)

$ time dd if=/dev/zero of=/run/media/jd/USB3_ST1-2K/test-wr-speed.txt 
bs=1M count=1000
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 57.6116 s, 18.2 MB/s

real    0m57.88s
user    0m0.00s
sys     0m1.28s

So much for 50MB/s write speed!!!!

Testing the read speed:

$ time dd if=/run/media/jd/USB3_ST1-2K/F3296296960 of=/dev/null bs=8M
392+1 records in
392+1 records out
3296296960 bytes (3.3 GB) copied, 106.6 s, 30.9 MB/s

real    1m46.62s
user    0m0.00s
sys     0m4.48s

So much for 160MB/s read.

I am going to diss this piece of  ... [expletive/deleted]