[Linaro-validation] USB drives are fantastic

[Paul Larson]

So you are talking about a USB connected 2.5" sata disk it seems?  We are
in the process of putting 16GB usb sticks in some of the machines.
Eventually, maybe all.  A few of the boards we have are problematic, such
as the origen.  Still others, such as the snowball, have bugs with USB that
would surely bite us here.  Also, since most (all?) of these boards don't
have an option to boot off of USB, it wouldn't get us any closer to
bootloader testing.

The one possible good thing with it, however, is that we could skip dealing
with an extra 2 partitions, have a normal partition layout, and even maybe
use LMC/LAMC to write the images, from the master image itself - thus
distributing the lmc load to the actual boards which would be ideal.  For
that reason alone, it might be worth considering.  However we should first
make sure of a few things.
1. that the current swath of boards will support it reasonably well (this
is iffy right now because of origen/snowball)
2. that we are reasonably safe for future, known/expected boards (I have
this nagging feeling that as soon as we did something like this, some new
member would join with a board that lacks usb... or *is* a usb stick -
cotton candy anyone?)
3. we should make sure that this doesn't interfere with dev platforms usb
testing schemes.  Currently we're adding those usb sticks so that they can
test on usb - not run off usb.

Thanks,
Paul Larson

On Fri, Jan 27, 2012 at 7:33 AM, Zygmunt Krynicki <
zygmunt.krynicki at linaro.org> wrote:

> Hi guys.
>
> This is just a note, perhaps we'll be able to go down this route
> (eventually) perhaps it will never be viable.
> SD cards are utter crap. USB disks are fantastic. I'm currently
> recovering my home server that died yesterday night due to a bad SD
> card. Luckily I kept the image as l-m-c would crash attempting to
> write it to my SD card adapter.
>
> Now I'm just finishing the final configuration bits (sadly those parts
> were lost with that card) and came to realize how painless and
> efficient a simple USB disk is. Would it be possible to change our
> deployment to use SD _just_ to store a recovery uboot and recovery
> kernel? Could we try to stick the master rootfs and test rootfs (and
> all those android partitions) directly on the HDD?
>
> PS: Apart from just working, it seems that current kernels have a big
> issue with very slow storage (like thumb drives and sd cards) and
> transparent huge tables. I cannot say it is directly the case on my
> iMX53 but "idle" system load on a regular SD card was around 4-5
> (writing to syslog, keeping up with small squid traffic of my home
> users) while the same system, with the same set of services on a run
> off the mill 2.5" HDD can barely climb above 0.5.
>
> Best regards
> ZK
>
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