[GTALUG] some USB sticks are slow!

[Lennart Sorensen]

On Sun, Sep 29, 2019 at 11:46:07AM -0400, D. Hugh Redelmeier via talk wrote:
> I bought some inexpensive SanDisk Cruzer Glide 16GB USB sticks from 
> Walmart last year.  Cheap.
> 
> Today I copied the CentOS 8 installation image onto one.
> 
>   time sudo dd if=CentOS-8-x86_64-1905-dvd1.iso of=/dev/sdg oflag=direct bs=16M
> 
> (I used a USB 3 port on my dessktop.)
> 
> It seemed to take a long time, so I did this to see if anything was 
> happening (the dd process' PID was 29047):
> 
>   sudo kill -s USER1 29047
> 
> Yes, there was progress, but not as much as I would expect.  The final 
> statistics were:
> 
>   425+1 records in
>   425+1 records out
>   7135559680 bytes (7.1 GB, 6.6 GiB) copied, 1560.63 s, 4.6 MB/s
> 
>   real	26m4.152s
>   user	0m0.072s
>   sys	0m4.706s
> 
> This amounts to about 4.56 MB/s.  That's even less than the poor
> Average Sustained Write Speed 7.64 MB/s reported here:
> 
>   <https://usb.userbenchmark.com/SpeedTest/2718/SanDisk-Cruzer-Glide>
> 
> Note: this stick hasn't been written to often.  It should not be near the 
> end of its life (that could slow down a flash device).

I have encountered Kinston USB3 sticks that are incredibly slow too.
Some of the cheap drives are complete garbage.

-- 
Len Sorensen