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Char devices for network interfaces

Char devices for network interfaces

Posted Oct 27, 2009 18:54 UTC (Tue) by mdomsch (subscriber, #5920)
Parent article: Char devices for network interfaces

Thanks everyone for your comments here. Network device naming has been a recurring problem for several years, and I appreciate seeing that it's still a big problem for people. That helps provide the incentive to getting it fixed.


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Char devices for network interfaces

Posted Oct 27, 2009 19:18 UTC (Tue) by dlang (✭ supporter ✭, #313) [Link]

unfortunately I see most of this work as being a solution in search of a problem.

there are a handful of cases (USB devices) where simple detection order is non-determinant, but the vast majority of devices fall into two categories

1. a single interface

2. simple detection order produces reliable device numbering

yes, when you change a card it can change the detection order, but that is true for every operating system, and is seldom a real big problem (because people are used to dealing with it)

the attempts to solve this problem end up causing more grief for many people, so much so that I doubt if the solution is worth it.

when you have a fairly rare problem to start with, your solution must be _very_ reliable for it to be better than doing nothing.

if you have a problem that affect 0.1% of the population, and your solution has an error rate of 1%, you have made life worse for 0.9% of the population.

this assumes that your solution is something that is deployed everywhere. creating a solution like this and having it option, used only in the case where people are experiencing problems to start with, you have a very different situation, then you are making life better for 0.099% of the population and not making life worse for anyone.

Char devices for network interfaces

Posted Oct 28, 2009 13:26 UTC (Wed) by mdomsch (subscriber, #5920) [Link]

If I didn't think it was really a problem, I wouldn't have spent so much time trying to find ways to solve it cleanly. :-)

By not changing how the kernel chooses to name devices, I can't break things for anyone. If they like the non-deterministic nature of device naming, and it works for them, great.

But that 0.1% you refer to, is around 20% of Dell's server sales, likewise for other server companies. Not insignificant to that userbase.

I'm not suggesting making this optional. I'm suggesting we add it into the base udev rules, where, if a platform provides additional information to help is provide "better" names, in addition to the normal kernel-provided names, that thsoe "better" names can be used too. For various definitions of "better", all simultaneously.

Yes, other OSs have this same problem too. I get to discuss the problem and approaches at solutions with them also.

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