Re: The "uniqueness" of UUIDs

From	<tomas@tuxteam.de>
Newsgroups	linux.debian.user
Subject	Re: The "uniqueness" of UUIDs
Date	2024-11-26 12:40 +0100
Message-ID	<JN25b-bKe6-1@gated-at.bofh.it> (permalink)
References	(2 earlier) <JMYEh-bHZp-9@gated-at.bofh.it> <JMZ7j-bIp0-1@gated-at.bofh.it> <JMZAl-bIAy-5@gated-at.bofh.it> <JMZK1-bITN-1@gated-at.bofh.it> <JN1LP-bK7f-5@gated-at.bofh.it>
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On Tue, Nov 26, 2024 at 12:16:59PM +0100, Roger Price wrote:
> On Tue, 26 Nov 2024, Nicolas George wrote:
> 
> > Roger Price (12024-11-26):
> > > You have to specify sda5 or sdb5.
> > There is nothing wrong with having to specify sda5 or sdb5.
> 
> Indeed, and it's the only way for Raid specification.  For example
> /proc/mdstat contains no mention of device UUIDs.
> 
> > It is only a problem if you want to specify now and expect it to be
> > still valid after the next reboot.
> 
> I'm guessing that this feature is something systemd has given us.

No. It has always been a problem [1]. It has become more acute the more
dynamic hardware has become. Nowadays, if you dangle off your machine
a bunch of storage devices on USB, the order they are seen depends on
the USB bus enumeration.

I'm not very happy with the so-called "persistent device names" myself
(that's why my disk is still /dev/sda, and my net interfaces wlan0 and
eth0), but I have the luxury to /know/ my hardware setup and it being
fairly stable.

Those stable device names were invented to solve a problem, and they
were there long before systemd.

Not a friend of systemd myself either, but it's important to stick
to the facts.

Cheers

[1] I stumbled first time upon this around the early 2000s, when we
   were making a small-series firewall device with 4 ethernet cards
   on it. Now which one is for "outside", which ones "inside"? Could
   we guarantee that, say, the first slot was always eth0? Turned out,
   no. Any BIOS update could mess up the order.
-- 
t

Thread

Re: Adding a new boot disk while keeping old disk George at Clug <Clug@goproject.info> - 2024-11-25 08:30 +0100
  Re: Adding a new boot disk while keeping old disk eben@gmx.us - 2024-11-25 16:10 +0100
    Re: Adding a new boot disk while keeping old disk David Wright <deblis@lionunicorn.co.uk> - 2024-11-25 16:30 +0100
      Re: Adding a new boot disk while keeping old disk Felix Miata <mrmazda@stanis.net> - 2024-11-25 16:40 +0100
        Re: Adding a new boot disk while keeping old disk George at Clug <Clug@goproject.info> - 2024-11-26 01:50 +0100
          The "uniqueness" of UUIDs Roger Price <debian@rogerprice.org> - 2024-11-26 09:00 +0100
            Re: The "uniqueness" of UUIDs Nicolas George <george@nsup.org> - 2024-11-26 09:10 +0100
              Re: The "uniqueness" of UUIDs Nicolas George <george@nsup.org> - 2024-11-26 09:40 +0100
              Re: The "uniqueness" of UUIDs Roger Price <debian@rogerprice.org> - 2024-11-26 09:50 +0100
            Re: The "uniqueness" of UUIDs Felix Miata <mrmazda@stanis.net> - 2024-11-26 09:30 +0100
              Re: The "uniqueness" of UUIDs Roger Price <debian@rogerprice.org> - 2024-11-26 10:00 +0100
                Re: The "uniqueness" of UUIDs Nicolas George <george@nsup.org> - 2024-11-26 10:10 +0100
                Re: The "uniqueness" of UUIDs Roger Price <debian@rogerprice.org> - 2024-11-26 12:20 +0100
                Re: The "uniqueness" of UUIDs <tomas@tuxteam.de> - 2024-11-26 12:40 +0100
                Re: The "uniqueness" of UUIDs Nicolas George <george@nsup.org> - 2024-11-26 12:40 +0100
                Re: The "uniqueness" of UUIDs <tomas@tuxteam.de> - 2024-11-26 10:30 +0100
                Re: The "uniqueness" of UUIDs Nicolas George <george@nsup.org> - 2024-11-26 11:00 +0100
                Re: The "uniqueness" of UUIDs Felix Miata <mrmazda@stanis.net> - 2024-11-26 15:00 +0100
                Re: The "uniqueness" of UUIDs <tomas@tuxteam.de> - 2024-11-26 16:00 +0100
                Re: The "uniqueness" of UUIDs Roger Price <debian@rogerprice.org> - 2024-11-26 16:40 +0100
                Re: The "uniqueness" of UUIDs <tomas@tuxteam.de> - 2024-11-26 18:50 +0100
                Re: The "uniqueness" of UUIDs Michael Stone <mstone@debian.org> - 2024-11-27 18:00 +0100
                Re: The "uniqueness" of UUIDs Roger Price <debian@rogerprice.org> - 2024-11-26 16:00 +0100
            Re: The "uniqueness" of UUIDs Arno Lehmann <al@its-lehmann.de> - 2024-11-26 09:30 +0100
              Re: The "uniqueness" of UUIDs Arno Lehmann <al@its-lehmann.de> - 2024-11-26 10:50 +0100
            Re: The "uniqueness" of UUIDs <tomas@tuxteam.de> - 2024-11-26 09:50 +0100
            Re: The "uniqueness" of UUIDs pocket@homemail.com - 2024-11-26 13:20 +0100
      Re: Adding a new boot disk while keeping old disk eben@gmx.us - 2024-11-25 18:30 +0100
        Re: Adding a new boot disk while keeping old disk Hans <hans.ullrich@loop.de> - 2024-11-25 21:00 +0100
    Re: Adding a new boot disk while keeping old disk <tomas@tuxteam.de> - 2024-11-25 18:00 +0100
      Re: Adding a new boot disk while keeping old disk Default User <hunguponcontent@gmail.com> - 2024-11-25 18:40 +0100
        Re: Adding a new boot disk while keeping old disk <tomas@tuxteam.de> - 2024-11-25 19:00 +0100
          Re: Adding a new boot disk while keeping old disk Default User <hunguponcontent@gmail.com> - 2024-11-25 20:10 +0100
        Re: Adding a new boot disk while keeping old disk eben@gmx.us - 2024-11-25 23:40 +0100
          Re: Adding a new boot disk while keeping old disk Greg Wooledge <greg@wooledge.org> - 2024-11-26 00:00 +0100
            Re: Adding a new boot disk while keeping old disk Felix Miata <mrmazda@stanis.net> - 2024-11-26 00:30 +0100
      Re: Adding a new boot disk while keeping old disk Max Nikulin <manikulin@gmail.com> - 2024-11-26 03:40 +0100

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