Can two USB flash drives conflict with each other?

[tech-lists]

On 02/03/2018 23:13, bob prohaska wrote:
> The obvious solution is "don't do that!", but if somebody can offer
> a more insightful explanation I'd be grateful. Using two USB flash
> drives simultaneously would be very useful.

I've found [this was a year ago, maybe two] that if I had two usb sticks
plugged in that sometimes they'd be detected in reverse order to what I
expected.

What I mean is that sometimes the device called /dev/da0 and the one
called /dev/da1 would swap on reboot. I suppose it would depend on which
one woke up first. So if I had made /dev/da0p1, allocated it as swap,
/dev/da0p1 as data, perhaps put the ports tree there, /dev/da1p1 as
data, perhaps used the entire device for data, sometimes it'd boot, look
at /dev/da0 which was /dev/da1 previously, not seen swap, and complained
loudly.

I think there is a way to wire device identities to names but it might
need GPT rather than MBR as a partitioning scheme. I worked around it by
labelling one of the usb sticks with sticky tape and ensuring it wasn't
plugged in before the other one when rebooting.

-- 
J.