From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tobias Geerinckx-Rice Subject: Re: Installer: GUIX_IMAGE as /dev/sda on some hardware? Date: Sat, 25 May 2019 13:58:20 +0200 Message-ID: <87r28mzqxv.fsf@nckx> References: <874l5i52i1.fsf@roquette.mug.biscuolo.net> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" Return-path: Received: from eggs.gnu.org ([209.51.188.92]:34057) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hUVYu-0001ZF-2B for help-guix@gnu.org; Sat, 25 May 2019 08:14:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hUVJp-0001Bn-Rp for help-guix@gnu.org; Sat, 25 May 2019 07:58:34 -0400 Received: from tobias.gr ([2001:470:7405::1]:38008) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hUVJp-00015E-6S for help-guix@gnu.org; Sat, 25 May 2019 07:58:33 -0400 Received: by tobias.gr (OpenSMTPD) with ESMTP id d573df45 for ; Sat, 25 May 2019 11:58:23 +0000 (UTC) Received: by submission.tobias.gr (OpenSMTPD) with ESMTPSA id 2c8cd0a0 (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256:NO) for ; Sat, 25 May 2019 11:58:22 +0000 (UTC) In-reply-to: <874l5i52i1.fsf@roquette.mug.biscuolo.net> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-guix-bounces+gcggh-help-guix=m.gmane.org@gnu.org Sender: "Help-Guix" To: help-guix@gnu.org --=-=-= Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable Giovanni Biscuolo wrote: > This is **very** important when installing grub, in fact grub > installation failed when instantiating my config.scm on the HP=20 > 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.=20 I guess they're fine (at your own risk=E2=80=A6) as short identifiers=20 during a single CLI session, but not across reboots. It just=20 often *happens* to work on most machines, which as we all know, is=20 the most dangerous kind of working. > 3. how is the USB media "relocated" to the last /dev/sd? device=20 > by the > installer? It's=E2=80=A6 not? Dev nodes & names are doled out by the kernel. As=20 you've discovered, they aren't to be relied on, and you should use=20 labels or UUIDs instead. Even if we'd pretend differently in the installer, for example=20 through artificially delayed probing for usb_storage devices,=20 things would still break when that lie would be exposed by adding=20 a new SATA drive, or when using a different (rescue) distro, or=E2=80=A6 > 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=20 depending on whether or not a USB keyboard was attached. It was=20 intended as a headless system; great fun debugging that!=20=20 I once corrupted a drive (luckily part of a RAID-1 array, but it=20 was still stupid of me) because the rescue CD scanned drives in a=20 different order than the distro I was used to. My first SATA motherboard enumerated drives differently between=20 cold and warm boots =E2=80=94 but only sometimes. I think it had=20 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 --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEARYKAB0WIQT12iAyS4c9C3o4dnINsP+IT1VteQUCXOkt3QAKCRANsP+IT1Vt eQdwAP4t07VZWP0IruwkgwDal90qmgRhWqA9HrN+gfagoDEe2QD9Ho8cZrBLAXMX RNanxIzClX3X9KA0t04eerabsZmWWwI= =R0Kh -----END PGP SIGNATURE----- --=-=-=--