Re: UUIDs (and devfs and major/minor numbers)

Richard Gooch (rgooch@atnf.csiro.au)
Wed, 16 Jun 1999 11:10:34 +1000


Chris Smith writes:
> This isn't a direct reply to anyone; just getting a thought out
> there. = It seems like most of the objection to devfs has been to
> its use of bus = locations rather than logical identifications of a
> disk in locating = them. But is it really any more difficult to
> build a logical volume = view of the disks in a system on top of
> devfs than it is to do the same = on top of a physical dev
> filesystem? Actually, I would think it's = easier, since programs
> like LILO just have to check devices that are = actually present for
> that UUID.

Firstly, devfs preserves the old names. So you have the choice.

Secondly, it probably makes sense to implement a nice volume
management scheme based on devfs+devfsd. Whether that functionality
should be put into devfsd or into scripts that devfsd calls is an open
question. I have not formed an opinion on that at this stage.

> PS. Maybe I missed this in the Union FS discussion, but has anyone =
> thought about the implications of unionfs in solving some of the =
> remaining hacks in devfs? Take, for example, required sockets for
> init. = Just a thought for the future. (Although from a purist
> perspective, = which I admit to occasionally holding, I'd say we
> probably ought to = start changing init programs to not use sockets
> in /dev -- that seems = like a poor place for such a socket)

Devfs supports sockets. You just create them from user space. It
doesn't cost anything extra, as sockets (and pipes) are just treated
as inodes to store. So even if you abolished sockets and pipes in
/dev, it wouldn't mean the devfs per-inode storage requirements would
be decreased.

Perhaps you thought that devfs creates the sockets? That is definately
not the case.

> ------=_NextPart_000_0076_01BEB735.28BE6A70
> Content-Type: text/html;

Yuk. HTML mail.

Regards,

Richard....

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