Re: devfs

Alan Cox (alan@lxorguk.ukuu.org.uk)
Fri, 7 Aug 1998 19:44:17 +0100 (BST)


> If a user-level program will make sure my /dev entries are accurate on
> boot-up, great! Is that possible?

Both by scsi ID and by volume as you can ask /dev/sda "ok whats your lun etc"
and thats all the kernel needs to do

> > often more convenient than device position. When it comes to volume management
> > of a big system both of these (and Solaris) are equally dumb approaches.
>
> Convenient for whom? Kernel programmers or admins/users?

Admins

> What would you suggest as a smart approach to volume management?

What matters isnt "which physical disk" its "where is the file system that
used to be /home". So UUID's are ideal for this (volume labelling).

> > And wherehasitgone is a tool to walk the disk tree and find a volume by uuid
> > and/or maybe ask LDAP/NIS maps to find it via NFS
>
> What would this look like in /etc/fstab?

I've no idea. That depends how you add such items to mount. ext2fs includes a
libuuid and all e2fs file systems have uuids. DOS fs has a serial number on
each disk, etc.

> P.S. I'm not arguing for devfs per se; simply arguing for a "canonical,
> never-out-of-date /dev" and "devices named by SCSI id".

Devices named by SCSI ID is IMHO a partial solution. I should be able to
take put a jaz disk of /home on any jaz drive on the machine and boot the
system happily. In an ideal world with LDAP or CORBA services running
I should be able to shove it in any machien on my network

Alan

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