Is fsck obsolet for journaling FS? - Was: How do I Automount [snip]

Tom H tomh0665 at gmail.com
Tue Dec 1 18:17:55 UTC 2015


On Tue, Dec 1, 2015 at 7:04 PM, Oliver Grawert <ogra at ubuntu.com> wrote:
> Am Dienstag, den 01.12.2015, 17:42 +0200 schrieb Tom H:
>> On Tue, Dec 1, 2015 at 5:18 PM, Oliver Grawert <ogra at ubuntu.com> wrote:


>>> the kernel properly re-assigns "root=UUID=...." from the kernel
>>> commandline (as set by all ubuntu installers) to /dev/root and will
>>> just boot away with it ... (virtual filesystems are handled by a file
>>> outside of /etc/fstab that gets parsed on boot)...
>>
>> This isn't the filesystem UUID.
>
> well, i meant the filesystem UUID that is used for root=, the kernel
> translates it to /dev/root since a few years by default (we even
> released fstab-less readonly images for the TI pandaboard in 2012 that
> relied on this fact).

I understood what you meant. :)

"/dev/root"! That's against upstream udev rules! LOL


>> It's the Partition Type GPT UID.
>>
>> IIRC, the systemd developers call the feature "discoverable partitions."
>>
> ah, so systemd can make out even more info from the GPT data !
> thanks i'll surely take a look at that (though these naming games from
> the systemd people that make things sound like an improvement start to
> scare me. their "PredictableNetworkInterfaceNames" [1] that we have to
> battle with nowadays are clearly a lot less predictable than just having
> eth0/wlan0 hardcoded across the board ;) )
>
> [1]
> http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames

There's one claim on [1] above that's incorrect. Kay S has said on
systemd-devel@ [2] in response to a NIC name change:

--8<------------------------------start---------------------------->8--
Btw, predictable means it will not change between reboots, that names
will not depend on enumeration order within the same setup. It does
not mean or promise, that added kernel/driver/firmware features will
not result in different names. That is expected behavior.
--8<-------------------------------end----------------------------->8--

And yet [1] has:

--8<------------------------------start---------------------------->8--
Stable interface names when kernels or drivers are updated/changed
--8<-------------------------------end----------------------------->8--

I don't know whether this is still the case but I used to be able to
modify the NIC names of VirtualBox VMs between ensX and enpYsZ by
changing the "adapter type". The "predictable network interface names"
spec over-promised with this claim...

I understand the logic of the change but there's no way that any
default's going to suit everyone. I've named NICs wiredX and wifiX
(and wanX when there's a box with wan/lan NICs) via
"/etc/udev/rules.d/" (or "/etc/systemd/network/" on some systems)
since the advent of biosdevname.

The "discoverable partitions" feature is on [3]. I've forgotten
Lennart P's motivation for this spec but it might have had to do with
having a state-less "/etc".

[2] http://lists.freedesktop.org/archives/systemd-devel/2015-October/034614.html

[3] http://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/



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