Questions tagged [overlayfs]
For questions concerning the Overlay Filesystem, which was included in Linux kernel 3.18.
83
questions
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14 views
Does remounting after changes to overlayfs underlying filesystem (UB) necessarily restore consistency?
The overlayfs documentation states that "if the underlying filesystem is changed, the behavior of the overlay is undefined, though it will not result in a crash or deadlock."
And, indeed, I'...
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0answers
23 views
OverlayFS - Is it possible to make overlay layer writable by anyone/specific user (different than original owner)?
Usecase:
I have a lot of production data and copying it for dev purposes would be unreal. I was thinking that OverlayFS could be a solution until a problem with permissions arised.
Let's assume i have ...
1
vote
1answer
12 views
How to use overlay mount to combine multiple directories with different sub directories?
I have downloaded several git repositories arranged in different source trees:
repoDirs1 (with child dirs including vendor)
repoDirs2 (with child dirs including vendor)
specialRepos1
specialRepos2
...
0
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0answers
36 views
Building a chroot with multiple upper dirs with overlayFS
I've got a simple chroot system, built using bind mounts. It resides in /opt/chroot.skel and it's built on Alpine.
Whenever I create a new user, I copy the files from /opt/chroot.skel, to a /opt/...
0
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0answers
45 views
How do I merge directories (read-only) using overlayfs?
I'm using overlayfs to merge three directories together as follows:
mount -t overlay overlay -o lowerdir=/dir1:/dir2:/dir3 /targetdir
This works partially according to my expectations. Some files ...
0
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0answers
6 views
Union mount filesystem with directed sources
I want to mount two filesystems, one a shared network filesystem and one a local filesystem. I want the network filesystem to be the home for most of the files. I want to have a list of files and ...
0
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0answers
9 views
Backing a directory using overlayFS
Is there a way to use overlayFS as backing operation?
I want to minimise data copy hence looking for different approaches. rsync is good option for backing data.
I was also going through LVM ...
0
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0answers
18 views
Switch lowerdir mount on overlayfs and remove NFS during ramdisk?
I'm using an NFS as the lowerdir of my overlayfs which is mounted at / and I'm attempting to sync it to the local disk /dev/sda1 but after the boot up is complete the NFS is still mounted and I'm not ...
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0answers
91 views
Mounting overlayfs with root patition stop working (for me)
I am trying to use rootfs as a lower point of new overlay mount point. Then I chroot to a new mount point and use it for test some packages and selflearning without harming real system. This was ...
1
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1answer
77 views
Proper way to backup an overlayfs
I'm using an overlayfs for different folders. Now I'm thinking about a backup and restore process. I didn't found anything via google, which answered my question.
An overlayfs has an upper, lower, ...
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0answers
65 views
How to make a bwrap + overlayfs + big rootfs scalable in terms of number of users?
Currently we have a setup on a build server where we have a rootfs image readable by all users (this image is generated by debootstrap and contains a minimal debian install with additional packages ...
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40 views
overlay-fs and editing upper directory with vim
For developing purposes, I am using the overlay-fs to merge custom changes to the base file structure. The merged-folder is used by a java application.
Now I experienced a strange behavior when using ...
3
votes
1answer
105 views
Stackable file system that works like a cache
I am looking for a stackable file system (Like UnionFS, aufs, and OverlayFS) that works similar to bcache or lvmcache but on file level - not on block level:
Reads will be done from top-layer. If the ...
1
vote
0answers
19 views
Mount order problem with systemd
Running Raspbian Buster. I have a loopback mount defined in fstab (bind option) where directory A is looped in as B.
I have another service started later (with systemd After=local-fs.target) that ...
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0answers
252 views
Difficulty mounting NFS as a layer in Overlayfs - bash: Operation not supported
Synopsis
I'm serving a NFS share from my local machine and, while mounting and accessing the share works as expected, when I attempt to reference the NFS as a lower directory in overlayfs, operations ...
0
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1answer
94 views
mount overlay upperdir under lowerdir?
I'm new to mounts and overlayfs. Is it possible to put upperdir under lowerdir? e.g.
volumes:
app:
driver: local
driver_opts:
type: overlay
o: lowerdir=${PWD},upperdir=${PWD}/...
1
vote
0answers
38 views
Is there any way around the length limitation in mount options?
Say I create a series of directories in the form "elem_###", where ### are the integers from 001 to 454, like so:
$ dirs=$(seq -felem_%03.0f 454 | tr '\n' ' ')
$ mkdir ${dirs}
I then use these ...
1
vote
1answer
117 views
change UID and GID file attributes on read only file system with mount [duplicate]
I have some file image of filesystem, and I want mount it with parameter changing files and directories UID and GID. I cannot change its parameters, because it is read-only filesystem.
I found some ...
1
vote
1answer
158 views
LXC Container with Overlayfs/Squashfs
We are using a Centos LXC container with the rootfs contained in a squashfs filesystem. I really like the fact that a user cannot edit the rootfs from the host.
During the development, developers ...
0
votes
2answers
563 views
Which file should I modify to mount a user overlay at boot time
I'm working on an embedded device with an arm cortex A9. The kernel version is 4.16.0 and is generated by buildroot 2018.05.
The storage memory is an mmc with several partition. U-boot reads the ...
1
vote
1answer
114 views
Which (if any) union filesystems allow you to mount them without an underlying filesystem?
I am considering using a union filesystem, such as aufs, UnionFS or OverlayFS.
I have a 138GB of Android source, to which I want to make minor changes and keep them under version control.
My plan is ...
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0answers
60 views
Overlay File System
Does the overlay file system always copy data when metadata of a file within the lower layer is changed? Is it possible to stack multiple lower layers?
2
votes
1answer
106 views
How to escape comma on mount options for overlay
To mount overlay it is given lowerdir, upperdir and workdir as options on mount(8) or data on mount(2), what logic is applied in order to escape commas? I have tried double commas and even quoting ...
3
votes
1answer
146 views
How to mount overlayfs where lower has child mounts?
I'm trying to setup an overlayfs for a chroot environment. The environment is made up from multiple read-only squashfs file systems (lower) and a single writable directory (upper).
The tricky part ...
3
votes
0answers
96 views
Why does cache work better in overlay2 than aufs?
A follow-up from this question.
After reading Docker Storage drivers from official doc I understood that overlay was faster than aufs because it had only one hard linked image layer.
But for ...
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0answers
28 views
How do I mount an overlay with dmsetup?
Simple question but I couldnāt find the answer :
Iāve an ext4 filesystem stored inside a squashfs volume (so readāonly) and an existing dm_snapshot_cow file for providing write access.
Whatās the ...
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0answers
85 views
Mount overlay directory containing NFS shared mount
I have a directory /tmp/usr/usr. In this path I mount NFS share from an other machine:
mount -t nfs IP:/export_path/usr /tmp/usr/usr
The contents of the remote /usr is there. But when I try to ...
2
votes
0answers
264 views
How to copy an overlay partition to a file, and how to mount such file?
I have a disk, with two partitions:
# fdisk -l
Disk /dev/mmcblk0: 7381 MB, 7381975040 bytes
4 heads, 16 sectors/track, 225280 cylinders
Units = cylinders of 64 * 512 = 32768 bytes
Device ...
1
vote
0answers
454 views
“Structure needs cleaning” error with Overlay FS
When I run this command:
mount -t overlay overlay -olowerdir=/some_lower_dir_0,upperdir=/some_upper_dir,workdir=/some_work_dir /some/overlay_dir
Everything works fine.
When I add more and more ...
1
vote
0answers
69 views
Why does rootless podman does not support overlfayfs mounts in non-ubuntu distributions?
In the rootless podman doc, it is stated that:
Can not use overlayfs driver, but does support fuse-overlayfs
Ubuntu supports non root overlay, but no other Linux distros do.
So ...
2
votes
0answers
65 views
Is it possible to mount an overlay over / right after boot?
Background:
I have an embedded system with both flash and SD storage.
Currently I use flash just for booting (uBoot, kernel, initramfs).
Root filesystem (/) is on SD (ext3 on /dev/mmcblk0p2).
I (...
2
votes
1answer
343 views
How can I use OverlayFS to “combine” multiple storage into one? Is this possible?
I've been looking into using OverlayFS. I'd like to be able to combine a bunch of already formatted, already containing data, hard drives. All hard drives are formatted with ext4.
The goal is to ...
0
votes
0answers
1k views
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
...
1
vote
1answer
365 views
Overlayfs over archivemount
I am trying to apply an overlay using overlayfs over a filesystem mounted with archivemount:
mkdir -p {upper,work,mount}
tar zcf somefile upper/ work/ mount/
mkdir tmp
archivemount -o allow_root -o ...
0
votes
2answers
151 views
Overlayfs inside archivemount
I am trying to mount an overlayfs inside an archivemount (as a follow-up to Layered or Virtual filesystem on Linux).
I am doing this:
mkdir -p {upper,work,mount}
tar zcf somefile upper/ work/ mount/
...
1
vote
0answers
470 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/...
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vote
0answers
287 views
Why overlayfs increases boot time?
Recently, I started using overlay filesystem. I'm using initram script (init=/sbin/myint) as described in Raspberry blog - raspberry overlay, yet, I noticed that it increases boot time significantly (...
0
votes
1answer
216 views
(user error) OverlayFS - files deleted in current merged dir (mountpoint) reappear when merged dir remounted as lower
On Debian Stretch (running as root) this the current behaviour:
# Create base directory
mkdir base
touch base/example
# Create merge, upper and work directories for 2 layers
mkdir layer1 layer1....
4
votes
1answer
3k views
using overlay2 on CentOS 7.4
How do I install and enable the overlay2 storage driver on CentOS 7?
I have done many google searches on this and I see that version 7.4 is required. So I typed the following commands to confirm ...
1
vote
1answer
111 views
Apache does not see files under overlay mount
have mounted overlay fs:
overlay on /srv/www/site type overlay (rw,relatime,lowerdir=/srv/www/site_orig,upperdir=/srv/www/site_custom,workdir=/srv/www/overlay_workdir)
I can see and edit files under ...
2
votes
2answers
3k 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 ...
3
votes
1answer
3k views
Mount root as overlayfs
I've been trying mount root (/) as overlayfs.
OS is booting over NFS to RAM. I've added a premount script in initrd, which creates the 'work', 'upper' and 'lower' directories.
During the boot ...
2
votes
1answer
1k views
Can not mount overlayfs inside initrd
I am trying to use read-only overlayfs(no workdir and upperdir) inside custom initrd.
This works fine in completely booted OS:
mkdir /tmp/ovl1 /tmp/ovl2 /tmp/merged
mount -t overlay none -o lowerdir=...
0
votes
1answer
740 views
OverlayFS over read only rootfs fail
I need to keep one system as much intact as possible. Only soldering of HW stuff is allowed :-). I need to install a test software package and this package must not stay there in the future.
I have a ...
8
votes
4answers
6k 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 (...
1
vote
2answers
154 views
Does overlayfs redirect opened files automatically on the fly?
or I should close file - then mount overlay - and then re-open file again?
i.e.
#!/bin/bash
my_background_process >log.txt &
...
pkill my_background_process
mount overlay
my_background_process ...
19
votes
2answers
7k views
Unionfs vs Aufs vs Overlayfs vs mhddfs, which one do I use
I have randomly been reading about union file system which enables a user to mount multiple filesystems on top of one another simultaneously.
However, am finding trouble deciding on which one to use(...
3
votes
2answers
1k views
Why can't /proc be a layer of a overlay file system (overlayfs) on linux?
Run the following commands on linux (4.4.59 and 4.9.8 are tested) and it will fail:
mkdir -p /tmp/proc
mount -t overlay overlay -o lowerdir=/proc:/tmp/proc /tmp/proc
and there is a error message in ...
2
votes
0answers
147 views
Proper way to create “persistent” RAM fs
I'm going to reduce SSD writes, so I'd like to keep changes to some directories (like /var/log or browser cache) in memory and syncing to permanent storage periodically. I should reduce memory size as ...
1
vote
1answer
551 views
Limit the size of tmpfs with overlayroot
Recently I found out that it's possible to use overlayroot with tmpfs to create stateless readonly root.
However I couldn't find any info about limiting the size of tmpfs. Is it possible?
