Arch Linux

anark10n

Member

Registered: 2012-10-13

Posts: 212

Random device mapping

So i ran a recent update on my arch, and nothing's particularly wrong, but now, it seems that the internal HDDs, which i mount using fstab, and my externals are assigned different device maps on every startup, with the external HDDs sometimes getting mapped before the internal ones. So for example, the two internals will be /dev/sdb and /dev/sdc on one startup, which is how it worked before, but the next startup, one will be /dev/sdc and /dev/sdj.

It's not a train-wreck, it behaving like this, but it is somewhat irritating. Does anyone know why this sudden behaviour?

Last edited by anark10n (2016-02-17 21:24:25)

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,654

Re: Random device mapping

My suggestion is to use UUIDs instead of device node names.

https://wiki.archlinux.org/index.php/Pe … ng#by-uuid

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anark10n

Member

Registered: 2012-10-13

Posts: 212

Re: Random device mapping

Yeah, I do use UUIDs to mount the internal drives, the externals i don't mount with fstab, i just click to mount them as and when i need them. It's just that when listed in a file browser, e.g. nemo, the devices are not arranged by they device name, but their device map, and the sequence changes with each startup. Like i said, it's no showstopper, just really irritating to have to deal with when i didn't have to before, and honestly, just looks sloppy.

alphaniner

Member

From: Ancapistan

Registered: 2010-07-12

Posts: 2,810

Re: Random device mapping

All things considered, I'd say this is a shortcoming of the file browser or whatever automount back end it uses. Do all your filesystems have labels? If not, try labeling one and see if the file browser lists it by label rather than devnode.

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ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,654

Re: Random device mapping

Well, one can create custom udev rules.  That would be my next tack.

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Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
The shortest way to ruin a country is to give power to demagogues.— Dionysius of Halicarnassus
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anark10n

Member

Registered: 2012-10-13

Posts: 212

Re: Random device mapping

@alphaniner, I don't quite get it. aren't /dev maps assigned by the kernel during boot? And yes, the drives do have labels, but it doesn't sort them by labels. Although, while on the desktop, if i disconnect an external drive it will appear last in the list if i reconnect, even it gets the same device map, so maybe it is the file browser, but this was also typical behaviour before the update.

@ewaller, i will look into that. Thanks for the suggestion.

alphaniner

Member

From: Ancapistan

Registered: 2010-07-12

Posts: 2,810

Re: Random device mapping

Maybe I'm the one not getting it. I thought the problem is that the file browser is displaying devnodes, and the fact that they change between boots makes it difficult to determine the one you want. I was hoping that the partitions just weren't labeled, and if they became labeled the file manager would display the label instead of the devnode.

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But whether the Constitution really be one thing, or another, this much is certain - that it has either authorized such a government as we have had, or has been powerless to prevent it. In either case, it is unfit to exist.
-Lysander Spooner

anark10n

Member

Registered: 2012-10-13

Posts: 212

Re: Random device mapping

The file browser does display the labels, but it sorts them according to the devnodes. The devnodes for the internal drives are assigned randomly now, which didn't happen before. Hope that clears up the issue i'm dealing with.