Questions tagged [overlayfs]
For questions concerning the Overlay Filesystem, which was included in Linux kernel 3.18.
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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
56 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 ...
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2answers
38 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
143 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/...
1
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0answers
150 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
171 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
373 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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0answers
131 views
Modify existing overlay mount
Is it possible to insert additional lower layers to an existing overlayfs mount?
The idea is to add new features to a running "chroot" so that they immediately see these changes in their root fs ...
0
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1answer
105 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
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1answer
1k 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
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1answer
70 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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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 ...
4
votes
1answer
1k 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 ...
0
votes
1answer
509 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=...
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1answer
306 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 ...
2
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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 (...
1
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2answers
99 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(...
4
votes
2answers
746 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 ...
3
votes
0answers
112 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 ...
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1answer
396 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
259 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
504 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
...
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1answer
447 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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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
648 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
788 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 ...
27
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2answers
8k 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 ...
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2answers
8k 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 ...
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vote
1answer
373 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
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0answers
757 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 ...
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1answer
183 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
905 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
2k 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
338 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
435 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
254 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 ...
5
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
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0answers
132 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 ...
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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 ...
4
votes
0answers
293 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
90 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 ...
4
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0answers
2k views
OverlayFS - How to make changes to upper filesystem persistent without unmounting?
I am using an USB drive to start a linux system which needs changes from time to time and also writes some logs. Flash drives tend to fail early if there are many write operations. That brought me to ...
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0answers
581 views
Using tar to backup and restore a path mounted with overlayfs
I have a system running OpenWRT with Linux 2.6.39.2.
In my filesystem, I have symlinks contained in /etc/rc.d on ROM and more symlinks contained in /overlay/etc/rc.d in flash.
overlayfs does a union ...
3
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1answer
774 views
overlayfs with a lot of directories
Say I have an arbitrary number of directories, labeled by numbers.
I also have the directory merge.
I can do
mount -t overlay -olowerdir=1:2:50 overlay merge
to get the contents of 1, 2, and 50 in ...
