Thank you you are right, it’s not currently possible on ubuntu 12.04.
The easiest solution for me right now is to switch to overlayfs which requires very little change to my code and that can do out of the box what I wanted to do with AuFS. Plus I read that overlayfs might integrate linux vanilla kernel in 3.10 and not AuFS. Thank you for your time, Regards, Robin On 16 Feb 2014, at 12:19, Michael Johnson - MJ <[1]m...@revmj.com> wrote: Hm... do you know which version of aufs you have on 12.04? I found this: [2]http://sourceforge.net/p/aufs/aufs3-standalone/ci/aufs3.2/tree/Documentat ion/filesystems/aufs/ Which says: Currently these features are dropped temporary from aufs3. See design/08plan.txt in detail. ... - nested mount, i.e. aufs as readonly no-whiteout branch of another aufs (robr) ... Looking at [3]http://sourceforge.net/p/aufs/aufs3-standalone/ci/aufs3.2/tree/Documen tation/filesystems/aufs/design/99plan.txt it looks like that feature was probably removed from aufs2. So I think the end result is that currently what you are trying to accomplish is not supported. I would guess you can accomplish what you are trying to by using a single, non-nested aufs mount by tweaking your create and copyup policies, but without knowing the reasoning behind what you are trying to accomplish, I can't say for certain. On Sun, Feb 16, 2014 at 2:57 AM, Robin Monjo <[4]robinmo...@gmail.com> wrote: Thank you for tour answer. I’m pretty sure that it’s possible since ubuntu 12.04. My guess is that they enabled the config you quoted in newer ubuntu kernel. Here is why: Man page for precise 12.04 Any filesystem can be a branch, But some are not accepted such like sysfs, procfs and unionfs. If you specify such filesystems as an aufs branch, aufs will return an error saying it is unsupported. Man page for earlier version (10.04) Any filesystem can be a branch, except aufs, sysfs, procfs and unionfs. If you specify such filesystems as an aufs branch, aufs will return an error saying it is unsupported. If you enable CONFIG_AUFS_ROBR, you can use aufs as a non-writable branch of another aufs. However, the simplest use case doesn’t work ... On 16 Feb 2014, at 09:17, Michael Johnson - MJ <[5]m...@revmj.com> wrote: From [6]http://aufs.sourceforge.net/aufs.html: Any filesystem can be a branch, except aufs, sysfs, procfs and unionfs. If you specify such filesystems as an aufs branch, aufs will return an error saying it is unsupported. If you enable CONFIG_AUFS_ROBR, you can use aufs as a non-writable branch of another aufs. My guess is that the documentation with the ubuntu version simply left aufs out of the docs. Notice that with the right compile options, newer versions can use aufs as a non-writable branch as you are trying to do. On Sat, Feb 15, 2014 at 12:22 PM, Robin Monjo <[7]robinmo...@gmail.com> wrote: Hello, My goal is to use an AuFS read only branch as another read only branch: I've got a directory dir0, then I make : mount -t aufs -o br=dir2=rw:dir0=ro none dir1 This gives me - dir0 - dir1 #read only dir0 - dir2 #write layer of dir1 I now want to use dir1 this way: mount -t aufs -o br=dir4=rw:dir1=ro none dir3 To get - dir0 - dir1 #read only dir0 - dir2 #write layer of dir0 - dir3 #read only dir1 (dir1 + dir2) - dir4 #write layer of dir3 I'm using ubuntu 12.04 and this should work according to aufs-tools man page: Any filesystem can be a branch, But some are not accepted such like sysfs, procfs and unionfs. If you specify such filesystems as an aufs branch, aufs will return an error saying it is unsupported. But I got this error: mount: wrong fs type, bad option, bad superblock on none, missing codepage or helper program, or other error (for several filesystems (e.g. nfs, cifs) you might need a /sbin/mount. helper program) In some cases useful info is found in syslog - try dmesg | tail or so and dmesg gives me aufs test_add:231:mount[3346]: unsupported filesystem, (aufs) Am I missing something here ? Regards, Robin -------------------------------------------------------------------------- ---- Android apps run on BlackBerry 10 Introducing the new BlackBerry 10.2.1 Runtime for Android apps. Now with support for Jelly Bean, Bluetooth, Mapview and more. Get your Android app in front of a whole new audience. Start now. [8]http://pubads.g.doubleclick.net/gampad/clk?id=124407151&iu=/4140/ostg.c lktrk -- Michael Johnson - MJ -- Michael Johnson - MJ References 1. mailto:m...@revmj.com 2. http://sourceforge.net/p/aufs/aufs3-standalone/ci/aufs3.2/tree/Documentation/filesystems/aufs/ 3. http://sourceforge.net/p/aufs/aufs3-standalone/ci/aufs3.2/tree/Documentation/filesystems/aufs/design/99plan.txt 4. mailto:robinmo...@gmail.com 5. mailto:m...@revmj.com 6. http://aufs.sourceforge.net/aufs.html 7. mailto:robinmo...@gmail.com 8. http://pubads.g.doubleclick.net/gampad/clk?id=124407151&iu=/4140/ostg.clktrk
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