From: Tobias Geerinckx-Rice <me@tobias.gr>
To: help-guix@gnu.org
Subject: Re: Installer: GUIX_IMAGE as /dev/sda on some hardware?
Date: Sat, 25 May 2019 13:58:20 +0200 [thread overview]
Message-ID: <87r28mzqxv.fsf@nckx> (raw)
In-Reply-To: <874l5i52i1.fsf@roquette.mug.biscuolo.net>
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Giovanni Biscuolo wrote:
> This is **very** important when installing grub, in fact grub
> installation failed when instantiating my config.scm on the HP
> ProLiant
> simply because it was on /dev/sda pointing to the USB media;
/dev/xdyN names have never been safe to use in this way, though.
I guess they're fine (at your own risk…) as short identifiers
during a single CLI session, but not across reboots. It just
often *happens* to work on most machines, which as we all know, is
the most dangerous kind of working.
> 3. how is the USB media "relocated" to the last /dev/sd? device
> by the
> installer?
It's… not? Dev nodes & names are doled out by the kernel. As
you've discovered, they aren't to be relied on, and you should use
labels or UUIDs instead.
Even if we'd pretend differently in the installer, for example
through artificially delayed probing for usb_storage devices,
things would still break when that lie would be exposed by adding
a new SATA drive, or when using a different (rescue) distro, or…
> 1. has anyone observed a similar issue?
>
> 2. what could have caused it?
I used to own a system that scanned drives in a different order
depending on whether or not a USB keyboard was attached. It was
intended as a headless system; great fun debugging that!
I once corrupted a drive (luckily part of a RAID-1 array, but it
was still stupid of me) because the rescue CD scanned drives in a
different order than the distro I was used to.
My first SATA motherboard enumerated drives differently between
cold and warm boots — but only sometimes. I think it had
something to do with spin-up times.
I could go on. I often do. Sorry.
Hoping to have scared you into using UUIDs,
T G-R
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next prev parent reply other threads:[~2019-05-25 12:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-25 9:04 Installer: GUIX_IMAGE as /dev/sda on some hardware? Giovanni Biscuolo
2019-05-25 11:58 ` Tobias Geerinckx-Rice [this message]
2019-05-25 13:16 ` Giovanni Biscuolo
2019-05-26 11:22 ` Tobias Geerinckx-Rice
2019-05-26 11:31 ` Tobias Geerinckx-Rice
2019-05-28 15:11 ` Ludovic Courtès
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