Questions tagged [overlayfs]
For questions concerning the Overlay Filesystem, which was included in Linux kernel 3.18.
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Protocol Error using Overlay FS with VirtualBox shared folders
I have a VirtualBox VM running Xenial. I want to share some folders with my host OS, but use the native filesystem for build artifacts due to running MySQL with InnoDB and some config I cannot change ...
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0answers
21 views
Does /etc/fstab overwrite mounts done during initramfs
I am experimenting with an Archlinux VM and two virtual disks. I am trying to mount / as an OverlayFS with, for example: sda1 containng the lowerdir and sdb1 containing the upperdir and the workdir.
...
2
votes
1answer
38 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 ...
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0answers
115 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
...
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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 ...
1
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1answer
89 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
48 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/
...
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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/...
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0answers
170 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 (...
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0answers
193 views
Overlayfs mounted, but get “read-only file system” on any write
I try a simple overlay example by mounting:
sudo mount -t overlay -o lowerdir=/tmp/lower,upperdir=/tmp/upper/upper, workdir=/tmp/upper/workdir none /tmp/overlay
(I run the full script from example ...
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0answers
431 views
Modify Ubuntu overlayroot @ boot time
The overlayroot package for Ubuntu is great, it really simplifies using overlayfs to protect the root volume from writes.
I am trying to mirror what I've been doing previously and cannot seem to do ...
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1answer
121 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....
1
vote
1answer
2k 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
79 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 ...
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vote
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 ...
3
votes
1answer
2k 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 ...
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votes
1answer
613 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
381 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 ...
4
votes
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 (...
1
vote
2answers
109 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 ...
8
votes
1answer
4k 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
782 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
121 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
443 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?
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0answers
287 views
Fedora 25 Live Persistent Overlay Not Working
I have just created a fresh Fedora 25 Xfce 32-bit Live USB using the following command:
livecd-iso-to-disk --noverify --reset-mbr --format --msdos \
--overlay-size-mb 1024 --home-size-mb 512 --...
1
vote
1answer
538 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
vote
1answer
509 views
Can overlayFS support more than two layers?
As far as i read documentation the overlayFS supports two layers - upper and lower. But is there possibility to increase it to three layers?
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votes
1answer
1k views
mounting /var as overlayfs
I'm running a read only filesystem on a raspberry pi so far everything works fine until i tried to mount /var as overlayfs for nginx and other services to work using this:
VAROVRL="-o lowerdir=/var,...
6
votes
1answer
1k views
OverlayFS Seamlessly Edit File in Lower Directory
I'm trying to set up a PXEboot environment in which the base system (served over NFS to the PXE clients) is read only, and the root filesystem is an overlayfs filesystem with the read-only NFS base ...
2
votes
0answers
693 views
creating an overlay directly over a mount (systemd-fstab-generator causes error)
I would like to create an overlay over my /var directory. I am using debian/stretch with a recent kernel and install. systemd 232. I am using something along the lines of (all lines with an implied ...
1
vote
1answer
856 views
Why is my overlayfs command not working?
The commands below should be creating a root overlay, such that any modifications to root will appear in /tmp/upper
However as you can see it does not appear to be working. Can anyone suggest what I ...
2
votes
1answer
1k views
Docker and OverlayFS
I'm trying to learn about docker and the overlayFS, as suggest by the official website, I installed the last kernel:
4.8.11-1.el7.elrepo.x86_64
and as suggest by them to ensure that overlay is good ...
30
votes
2answers
9k views
Linux Filesystem Overlay - what is workdir used for? (OverlayFS)
OverlayFS has a workdir option, beside two other directories lowerdir and upperdir, which needs to be an empty directory.
Unfortunately the kernel documentation of overlayfs does not talk much about ...
6
votes
2answers
9k views
How to use OverlayFS to protect the root filesystem?
How do I correctly use OverlayFS to protect my root filesystem?
I have an embedded system that boots and runs from an SD card. Since it will experience sudden power loss, I want to protect the root ...
1
vote
1answer
378 views
linux - OOM / swap not being used
I am getting Out of Memory errors while my swap isn't touched. I have 4GB of ram and 4GB of swap space. I enabled the swap via swapon and when doing free, I see the swap listed there.
I'm thinking ...
2
votes
0answers
840 views
Is there anyway to modify one file and sync to the lower directory in OverlayFs?
I know about the
overlayfs
that it treats lower directory as a read-only and copy_up when we want to modify the lower file
so is there any way to modify the lower file and it can copy the modified ...
1
vote
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
votes
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
3k views
How can I delete changes from an overlay fs?
I have an embedded device running BusyBox, there are a number of directories mounted with overlayfs with work and data directories mounted on separate UBI partitions using the following style of ...
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0answers
342 views
How to reflect changes made to original LXC container on overlayFS snapshots?
In order to make updates easier and limit there size, I created a base LXC container, let's say c1, where i installed and configure a few default packages (using apt) which are common to all my ...
4
votes
1answer
464 views
Mounting Overlayfs in a user namespace
Is it possible to mount an Overlayfs filesystem as an unprivileged user in a user namespace in Linux kernels >4.3.3; it seems that the fix to this vulnerability has blocked this functionality entirely....
2
votes
2answers
1k views
what occupy space at overlayfs
I have a linux with a read only root filesystem and a read-write overlayfs mounted over it:
# mount
overlayfs on / type overlayfs (rw,relatime,lowerdir=/root_ro/,upperdir=/root_rw/)
...
The ...
2
votes
1answer
258 views
Mount a large squashfs in a way that allows random writes (to a separate filesystem)?
I just received a few-dozen-gigabyte squashfs that contains a PostgreSQL database. In order to be able to conveniently query it, I need to have a write access, which makes it complicated. Is there a ...
4
votes
1answer
2k views
Merge two NFS shares with OverlayFS
I have two directories (a and b), which are NFS shares with files foo.txt and bar.txt:
I want merge this two directories to directory merge (does not have to be writable)
this is possible by command:...
5
votes
2answers
10k views
overlayfs: missing 'workdir' on CloneZilla start
I would clone my partition /dev/sda1 on Ubuntu 14.04.
I've downloaded Clonezilla in order to clone this partition and be able to reinstall it later.
As recommended on the CloneZilla's website, I used ...
3
votes
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 ...
7
votes
1answer
2k views
How to modify a lower file through an OverlayFS directory?
I want Linux's OverlayFS to behave like AUFS when writing to a lower file. I want it to write through to the lower directory. For example, I have two files named L/lower and U/upper.
mount -t ...
5
votes
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 ...
3
votes
2answers
4k views
OverlayFS doesn't work with unprivileged user namespace
OverlayFS mount works weird when accessed from within the unprivileged user namespace. Best to be explained in example:
~# uname -a
Linux host 4.1.0-1-amd64 #1 SMP Debian 4.1.3-1 (2015-08-03) x86_64 ...
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0answers
91 views
Light file copy with diff
Is there a way to copy a file by creating another instance of it, that is not created as a hard copy, but by a link with the difference that any edit to that file will be saved in an diff file?
I ...
