Questions tagged [union-mount]

A union mount creates an overlay of several filesystems on one mount point

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Overlay : filesystem not supported on lowerdir

I tried to mount an external storage device (a usb flash drive) with overlay (as the lowerdir the usb and as upper a temporary ramdisk) mkdir /data mkdir /data/lower mkdir /data/rw mkdir /data/root ...
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0answers
26 views

How do I remount / on my live CD to include /mnt/sda1/overlaytest as upperdir?

How do I remount / on my live CD to include /mnt/sda1/overlaytest as upperdir? I tried: { mountpoint /mnt/sda1 && sudo mkdir /mnt/sda1/overlaytest && mount -v -o remount -t ...
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0answers
231 views

What are the consequences of specifying same directory overlay upper/workdir and merged?

I wanted to have a simple RO overlay of my root for use in my container, but for whatever reason it didn't work: $ sudo mount -t overlay overlay -o lowerdir=/ /var/lib/machines/test/ mount: /var/lib/...
0
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1answer
79 views

FUSE overlay mount with colon in path

Is it possible to do an overlay mount when one of the paths has a colon in it? All of the FUSE overlay mounting solutions I've looked at use a colon to separate the paths in the overlay, and I can't ...
1
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2answers
263 views

How safe is it to use unionfs in FreeBSD?

From man mount_unionfs: BUGS: THIS FILE SYSTEM TYPE IS NOT YET FULLY SUPPORTED (READ: IT DOESN'T WORK) AND USING IT MAY, IN FACT, DESTROY DATA ON YOUR SYSTEM. USE AT YOUR OWN RISK. BEWARE OF DOG. ...
0
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1answer
80 views

How to use loopback to access the lower files of a unionfs, in FreeBSD?

From man mount_unionfs: If a file exists in the upper layer then there is no way to access a file with the same name in the lower layer. If necessary, a combination of loopback and union mounts can ...
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2answers
1k views

Mount /var/logs as tmpfs, with help of overlayfs to save changes sometimes

Instead of just mounting tmpfs on /var/log I want to use overlayfs. /var/log are writable tmpfs, but containing files were there before tmpfs mount. This old files are not in memory of tmpfs but in ...
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3answers
3k views

Merge changes to upper filesystem to lower filesystem in Linux Overlay (OverlayFS) mount

I would like to be able to merge changes from the upper filesystem of an overlay mount to a lower filesystem. I am interested both online (i.e. merge while the overlay is mounted) and offline (...
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0answers
310 views

Creating a mount with `rw` support when drive does not support read and write simultaneously [closed]

Rclone offers opportunity to sync with cloud, namely, Dropbox, GDrive, ... Also rclone can mount the cloud storage which sounds interesting to what I am trying to accomplish - a single synchronization ...
6
votes
1answer
665 views

Union mount options in Fedora

I've grown up a Debian/Ubuntu guy and I'm learning Fedora by trying to recreate the services my Ubuntu trusty box currently provides. However, I'm trying to recreate a union mount and don't see any ...
1
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1answer
539 views

Why mounting overlayfs with root as lowerdir produce an empty /proc in mergedir?

Here's the test case: #!/bin/bash more="$@" saved="$EUID" if [ "$EUID" = "0" ]; then echo "don't run as root" exit fi m="/tmp/mount-point" exec sudo unshare -m /bin/bash <<UNSHARED ...
1
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1answer
195 views

Mount unionfs (or aufs) branches fed from stdin?

Is it possible to feed the branch paths from stdin to the mount (or mount_unionfs) command, instead of supplying them as arguments or from a file? cat ~/dirs_with_photos.txt | mount -t unionfs I don'...
5
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1answer
945 views

Can I use a read-write root filesystem disk image as an OverlayFS upperdir?

Is it possible to union-mount an existing disk image containing a root filesystem to the upperdir of an overlayfs mount for read-write access? I'm trying to union-mount some old disk images to a /tmp/...
2
votes
1answer
569 views

How can I create an union merging / and another directory, on / itself?

Say, we initially have / with the following contents: /bin/foo /usr/bin/bar /usr/lib/libfoo.so We also have another directory, say /stuff, with the contents: usr/lib/mystuff/mystuff.so etc/foo/qux/...
8
votes
1answer
3k views

Union mount on Linux

A union mount presents a combined view of multiple directories (branches) in a single hierarchy. Ok, but how do I use one in practice, and which one? Many union mount technologies are available on a ...
3
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0answers
140 views

overlay-filesystem that can differentiate between metadata and file content?

AFAIK with aufs when a file is touched (ie. only it's metadata changed, not it's contents), then the copy-on-write mechanism of the file system will copy the whole file into the r/w layer, essentially ...
5
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0answers
305 views

OverlayFS: Is mounting /foo/lower:/foo/upper to /foo safe?

Consider the following union mount: mount -t overlay -o lowerdir=/.pre-foo/lower,upperdir=/.pre-foo/upper,workdir=/.pre-foo/work overlay /foo I would like to obfuscate that /.pre-foo to minimize the ...
2
votes
1answer
665 views

Making aufs union mounts read-write

So I've got two systems, lucyvanpelt and schroeder. lucyvanpelt's /home is exported read-write to schroeder via NFS. Its location on schroeder is /mnt/home/lucyvanpelt I want to union-mount it with ...
2
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1answer
3k views

SquashFS+UnionFS as root filesystem?

What's an easy way to to use a union filesystem (read-only SquashFS + R/W overlay) as /? I'm thinking of using a custom boot script as the kernel init= argument. The script would mount the SquashFS + ...
7
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3answers
5k views

Mount directory onto root

I have a folder containing certain files. Is there a way to mount it onto /, so that the contents of a given directory appear in the corresponding locations in /? In my case, the directories contain ...