Thanks Neil for the quick reply.

I have one server (which is more of a powerful desktop - https://system76.com/desktops/ratel) . It can handle 4 devices most of the time. Occasionally we get into the USB fastboot issue.

With a general powered USB hub i have been able to take it up to 6 devices. The flock method in dispatcher of restricting fastboot is pretty good, but not foolproof.

I got one cambrionix USB hub, but that is expensive.

I didn't quite understand how LXC will help with fastboot.

My understanding of LXC was that it replaces KVM for a multinode setup as it is more lightweight and supports usb for things like adb over USB.

Thanks

Sandeep

On Fri, Jun 24, 2016 at 10:47 AM, Neil Williams <neil.williams@linaro.org> wrote:

On 24 June 2016 at 17:40, Sandeep Chawla <sandeep@cyngn.com> wrote:
> Hello,
>
> I have a lava setup and right now running two single instance servers. These
> are pretty high end servers are handling 4-5 Android devices over USB

Are these devices connected directly to the server or are you using
powered USB hubs? (Servers themselves don't always have more than 1 or
2 USB ports.)

> I need to expand that to multi node setup with maximum DUTs connected to one
> dispatcher.

Caution: there are problems there, completely unrelated to LAVA, where
the USB stack and fastboot end up causing jobs to sit there and wait
for each other when there are multiple USB / adb devices on one
dispatcher. We've moved to using LXC in LAVA V2 to solve these
problems.

> The target is only to have android DUTs so that implies a very stable USB
> hub and stack on the dispatcher machines.
>
> I used a couple of off the shelf desktops in the past and the USB stack
> could not handle more than 1 device at a time.

That is a common experience - the Cambridge lab also limits the number
of USB devices per dispatcher. Again, we're using LXC to isolate the
USB devices and fastboot/adb from each other. The Cambridge lab is
also working with a small company with some specialised USB devices
(not cheap).

http://www.cambrionix.com/

> Any suggestions for hardware that is proven to be solid for dispatchers.

Mass market USB stacks can be a real pain - no matter what gets
recommended, what it says on the label or packaging is no guarantee of
the same chips inside.

Adding Dave to CC as he has more direct experience of the lab setup,
including the Cambrionix units.

(Also, I'm about to head off to DebConf16 when I'll not be as easily
contactable as usual.)

--

Neil Williams
=============
neil.williams@linaro.org
http://www.linux.codehelp.co.uk/