Testing removable media

[Jeff Lane]

On 08/15/2012 09:32 AM, Gema Gomez wrote:
> Hey Jeff,
>
> On 15/08/12 14:07, Jeff Lane wrote:
>> Hey folks,
>>
>> I wanted to ask a quick and dirty question:
>>
>> What would you consider a "Stress" test of removable media like USB Keys
>> & SD/SDHC cards?
>
> What are you trying to test exactly, the speed of the HW itself or the
> throughput that you get from a particular driver/implementation? The
> file-system on that media? The time it takes to wear off? What is it
> that you are trying to stress?

That's a good question, and in reality, it's just a general "Lets do a 
whole lot of stuff to this removable device at once and make sure it 
doesn't fall over".  Not looking to explore specific facets, more like 
just general load testing.  I think your ideas below address the spirit 
of the exercise.

>>
>> I'm working on enhancing a script and so far, the only idea put forth
>> was to do multiple simultaneous read/writes (like 100 at a time). But is
>> that a realistic stress test for something meant to be small, light but
>> with a very slow transfer speed?
>
> It all depends on what you are trying to achieve. There are many
> variables and there are file-system implementations that can interfere
> with your measurements.
>
>> Or would it be more appropriate to do something more realistic like,
>> transfer increasingly large files up to a pre-determined size (perhaps a
>> 2GB file size max?)
>
> Maybe for an SD card more realistic would be to transfer 3-4 MB files,
> but tons of them, like people do with cameras/music. Again back to my
> question of what you are trying to stress.

Currently, I have something that does X concurrent threads that write 
data to a device, checksum the data and compare that checksum to the 
original file for verification.  I think your suggestion is more inline 
with real-world usage (e.g. the camera use, or transferring a library of 
music, etc) and may be more valuable as this is really, as mentioned 
above, a general load test, not necessarily stressing or looking at a 
particular piece in the stack.

>
> Thanks,
> Gema
>
>>
>> Cheers,
>>
>> Jeff
>>
>
>


-- 
Jeff Lane - Hardware Certification Engineer and Test Tools Developer
Ubuntu Ham: W4KDH
Freenode IRC: bladernr or bladernr_
gpg: 1024D/3A14B2DD 8C88 B076 0DD7 B404 1417  C466 4ABD 3635 3A14 B2DD