Re: [systemd-devel] Booting with USB flash disk installed results in wrong disk numbering
Am 05.02.2013 14:30, schrieb Baurzhan Muftakhidinov: > What concerns me here is that there is no consistency on less powerful > machine. There is no consistency. Period. Not on more powerful and not on less powerful machines. There never was, there never will be. In some form, this "problem" has existed for at least a decade, yet people still consider it a new problem because they've just now seen it for the first time. Udev has provided persistent and predictable naming schemes for hard drives for a long time (almost a decade probably). You MUST use those. signature.asc Description: OpenPGP digital signature ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Booting with USB flash disk installed results in wrong disk numbering
'Twas brillig, and Baurzhan Muftakhidinov at 05/02/13 13:30 did gyre and gimble: > Alright, > I've tried on netbook and on relatively powerful laptop to boot 10 times > latest ArchLinux's archboot image from the USB drive. > > On laptop, hard disk was /dev/sda 10 times out of 10 tries, > > On netbook, only 3 times hard disk was /dev/sda and 7 times USB drive > became /dev/sda. > > What concerns me here is that there is no consistency on less powerful > machine. > > So I should just believe in the RANDOM choice on every boot on my netbook? > > On Debian with sysvinit it works just fine. When I change sysvinit to > systemd (kernel and udev are the same), > I see the situation I am talking here. > > This is what I asked for, maybe there is some kind of timeout for > detecting disks. As others have already commented, you simply should not use /dev/sd* at all in any definition either on the kernel command line or in your fstab. Distros switched many years ago to using UUIDs for fstab and kernel command line entries - long before systemd existed. Forget those /dev/sd* names, they are meaningless. Use the UUID or use the LABEL. Anything else is just going to break in confusing ways. Solutions for the problem already exist - better just to use them. Col -- Colin Guthrie gmane(at)colin.guthr.ie http://colin.guthr.ie/ Day Job: Tribalogic Limited http://www.tribalogic.net/ Open Source: Mageia Contributor http://www.mageia.org/ PulseAudio Hacker http://www.pulseaudio.org/ Trac Hacker http://trac.edgewall.org/ ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Booting with USB flash disk installed results in wrong disk numbering
Am 05.02.2013 14:30, schrieb Baurzhan Muftakhidinov: > I've tried on netbook and on relatively powerful laptop to boot 10 times > latest ArchLinux's archboot image from the USB drive. > > On laptop, hard disk was /dev/sda 10 times out of 10 tries, > On netbook, only 3 times hard disk was /dev/sda and 7 times USB drive > became /dev/sda. that's what random means :-( > What concerns me here is that there is no consistency on less powerful > machine. > So I should just believe in the RANDOM choice on every boot on my netbook? yes > On Debian with sysvinit it works just fine. When I change sysvinit to > systemd (kernel and udev are the same), > I see the situation I am talking here. UUID's or at list LABEL= for mount-points were invented long before systemd became a topic, finally it was ALWAYS luck to get the same /dev/sdX but since this is meaningless because for years anything and anybody refers UUID's nonody is wasting his time to try make it more stable for no benefit signature.asc Description: OpenPGP digital signature ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Booting with USB flash disk installed results in wrong disk numbering
Alright, I've tried on netbook and on relatively powerful laptop to boot 10 times latest ArchLinux's archboot image from the USB drive. On laptop, hard disk was /dev/sda 10 times out of 10 tries, On netbook, only 3 times hard disk was /dev/sda and 7 times USB drive became /dev/sda. What concerns me here is that there is no consistency on less powerful machine. So I should just believe in the RANDOM choice on every boot on my netbook? On Debian with sysvinit it works just fine. When I change sysvinit to systemd (kernel and udev are the same), I see the situation I am talking here. This is what I asked for, maybe there is some kind of timeout for detecting disks. Thanks. On Tue, Feb 5, 2013 at 3:36 PM, Tom Gundersen wrote: > On Tue, Feb 5, 2013 at 9:30 AM, Baurzhan Muftakhidinov > wrote: >> I have systemd in both Arch and Debian sid, on my netbook. >> I have noticed that when I power on netbook with USB flash disk installed, >> this USB drive sometimes becomes /dev/sda. >> >> Is this correct? How can I ensure that hard disk is first, at every boot? > > You cannot. The kernel will enumerate the devices in the order it > becomes aware of them, which is not deterministic. To get reliable > device names you should use /dev/disk/by-*/* which are guaranteed to > be stable between boots. Alternatively, as Reindl suggests, both the > kernel commandline and fstab (and probably others) support specifying > devices by UUID=, LABEL=, PARTUUID= or PARTLABEL=, which correspond to > the /dev/disk/by-* entries. > > HTH, > > Tom ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Booting with USB flash disk installed results in wrong disk numbering
On Tue, Feb 5, 2013 at 9:30 AM, Baurzhan Muftakhidinov wrote: > I have systemd in both Arch and Debian sid, on my netbook. > I have noticed that when I power on netbook with USB flash disk installed, > this USB drive sometimes becomes /dev/sda. > > Is this correct? How can I ensure that hard disk is first, at every boot? You cannot. The kernel will enumerate the devices in the order it becomes aware of them, which is not deterministic. To get reliable device names you should use /dev/disk/by-*/* which are guaranteed to be stable between boots. Alternatively, as Reindl suggests, both the kernel commandline and fstab (and probably others) support specifying devices by UUID=, LABEL=, PARTUUID= or PARTLABEL=, which correspond to the /dev/disk/by-* entries. HTH, Tom ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Booting with USB flash disk installed results in wrong disk numbering
Am 05.02.2013 09:30, schrieb Baurzhan Muftakhidinov: > Hello, > > I have systemd in both Arch and Debian sid, on my netbook. > I have noticed that when I power on netbook with USB flash disk installed, > this USB drive sometimes becomes /dev/sda. > > Is this correct? How can I ensure that hard disk is first, at every boot? for what? disks are mounted these days with UUID's an the /dev/sdx is meaningless signature.asc Description: OpenPGP digital signature ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
