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Re: (Semi-random) thoughts on device tree structure and devfs

Masao Uebayashi wrote:
"More or less", because I don't have all the details. If you were to post
the dmesg from your booting, I could give you the exact thing.

One of the problems is that such a long term user like you have to
know the full detailed dmesg and analyze it.  That doesn't meet my
goals.  Imagize admins hot-swap multiple disks/NICs on missiong
critical servers.

Two things comes to mind here:
1) Hot-swapping disks and so on have nothing to do with interpreting dmesg, or setting up a configuration. The configuration should already have been done, and working.

2) As I mentioned before - I know I have seen a program which will spit out the config neccesary to actually get a static setup in place, based on the current configuration. So, if you have managed to get a setup that is correct just now, you can basically "snapshot" it, and you'll get the same setup every time after that. And it does not take an "expert" to just use that program.

So I can't say that this should be a problem. Basically, we already today have a way of getting a predictable device enumeration, which is repeatable, even in the face of other random changes to the hardware. So I don't see the point in why you want to change this. And moving it into a filesystem makes it awkward, more difficult in some ways, and in short is just a bunch of work that gives nothing. Wouldn't it be better to spend that energy on something that actually will buy us something?

And of course I have to know the full details. Just as I would have to know the full details to know the path in your filesystem, if that were to reflect the hardware configuration. How would you know where to find your disk in the file system if you didn't know exactly all the buses and instances that lay between the root and your disk?

Hmm, I just realized that I didn't completely follow how your file system design will even solve which controller gets which path. Maybe it was in your original mail, but I have forgotten that detail in that case. If you have two disk controllers on one bus, how do you decide which is "0", and which is "1"?


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