Questions tagged [root-filesystem]

The root filesystem (`/`) contains the kernel and utilities needed to boot a system.

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Change permisions of a file with my cat's help

root@system:~# less myfile -bash: /bin/less: Input/output error The root filesystem is dead. But my cat is still alive (in my memory): root@system:~# cat > /tmp/somefile C^d root@system:~# He's ...
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How is /etc/fstab accessed before root is mounted?

I was making some changes to /etc/fstab, when this chicken and egg question occurred to me - if /etc/fstab contains the instructions for mounting the file systems, including the root partition, then ...
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What are the minimum root filesystem applications that are required to fully boot linux?

It's a question about user space applications, but hear me out! Three "applications", so to speak, are required to boot a functional distribution of Linux: Bootloader - For embedded typically that's ...
15
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2answers
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Is using a read only root file system a good idea for embedded setup?

I have been tasked with running Linux as an operating system on an embedded device. The target has an x86 processor and has 8 GB CompactFlash device for storage. I have managed to use buildroot to ...
15
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4answers
30k views

Mount root filesystem from initramfs

It's a common scenario. For whatever reason, the initramfs (OpenSUSE, in case it matters) has failed to find the root filesystem, so it drops you into a rescue shell. I know perfectly well what device ...
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4answers
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Does POSIX limit the number of directories in the os root?

I'm trying to learn the POSIX standard. When using Unix, I have /bin, /etc, /dev, /media, and usually /opt, but is that standardized or up to your spec implementation? Could there be many directories ...
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3answers
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Why on some Linux systems, does the root filesystem appear as /dev/root instead of /dev/<real device node>in mtab?

I've seen on various Linux systems where instead of the real device node (for example: /dev/sda1), the root device appears as /dev/root, or instead of the real filesystem, mtab says it is a filesystem ...
10
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3answers
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Can virtfs/9p be used as root file system?

Is it possible to use a folder shared from the host to the guest via virtfs/9p as the root file system inside the guest? Loosely related to my previous question: Can virtfs/9p be used to share the ...
9
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3answers
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Any reason for encrypted /?

I am a big fan of linux and like trying out new distros now and then. I usually have my home folders and roots in a lvm atop an encrypted partition, but this tends to become cumbersome with every ...
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2answers
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Deleted /tmp accidently

Accidently, I ran sudo rm -r /tmp, is that a problem ? I recreated it using sudo mkdir /tmp, does that fix the problem ? After I recreated the directory, In the places section in the sidebar in ...
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What is zImage, rootfs

I am very much new to Embedded Linux. We use poky build system. We just use bitbake linux-imx command to build the kernel. It generates some files zImage, rootfs, uboot and also a sdcard image. We ...
7
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1answer
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what does mount -o remount,ro / actually do (under the hood)

To remount a mounted filesystem to read-only, I can use following command: mount -o remount,ro /foo This is used for example in the shutdown sequence, where root filesystem (/) is remounted read-...
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Unable to find root device ''

ERROR: device '' not found. Skipping fsck. ERROR: Unable to find root device ''. You are being dropped to recovery shell I've been trying to install Arch Linux for some time, and keep running into ...
6
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1answer
455 views

Can I install GNU/Linux on a FAT drive?

Out of curiosity, is this possible nowadays? I remember some old Slackware versions did support FAT root partition but I am not sure if this is possible with modern kernels and if there are any ...
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5answers
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How big should the rootfs partition should be on Arch Linux?

I've installed ArchLinux yesterday and set up a 10 GB partition for the root file system, 256 MB for swap, and the rest (456 GB) for my /home. However I still have 4.0 GB left on my root file system ...
6
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1answer
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What is the purpose of listing the rootfs in /etc/fstab?

In BuildRoot 2015.08.1 /etc/fstab contains the following line. /dev/root / ext2 rw,noauto 0 1 On my encrypted Ubuntu laptop /etc/fstab contains the following line. /dev/mapper/ubuntu--vg-root / ...
6
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1answer
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How creation of new USB device file in /dev/bus/usb/001/ directory work?

I noticed that every time I connect a USB device, a new device gets created in the /dev/bus/usb/001/ directory. Further on each reconnection of the same device, the "Device Number" and "ID" change. ...
6
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1answer
838 views

How to Run Tunefs on Root Filesystem in FreeBSD?

I want to enable ACLs for a FreeBSD 11 system. According to the FreeBSD Handbook this can be done in two ways: By using a mount option -- mount -o acls By modifying a superblock -- tunefs -a enable ...
5
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2answers
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Multiple root options in Linux command line

My kernel command line looks like this: root=31:0 ro noinitrd console=ttyS0,115200 root=/dev/mtdblock2 rootfstype=squashfs I think the first root entry identifies a disk by its major and minor ...
5
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3answers
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Ensure that loopback root and host are unmounted on shutdown

I'm trying to setup a Linux system that runs from an LVM-formatted image file. After some tinkering with the initramfs and boot options I managed to make it up and running by mounting the host file ...
5
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2answers
421 views

What is the proper way to unlock a root filesystem spanning two LUKS devices by only entering the password once, using systemd?

I have been having a lot of issues getting an encrypted multi-disk root filesystem to boot up reliably under systemd on Debian Jessie while only having to enter the password once. Previously I've ...
5
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1answer
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Built the kernel with NFS support but not getting /dev/nfs

I'm trying to build kernel 3.13.9, fetched using apt-get source, and built in a clean debootstrap chroot (both host and chroot being installations of Ubuntu Trusty). My goal is to boot a diskless ...
5
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1answer
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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/...
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2answers
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Are Linux drivers part of the kernel or the rootfs

I have been working on a board with an embedded ARM processor. To get it to boot I have to add a bootloader, a linux kernel and a disk image containing the root file system. This disk image is ...
4
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2answers
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How to reduce LVM for root partition?

I am trying to reduce the space dedicated to root LVM since I don't really need it and I am having a few doubts. Below is the output for lvdisplay: # lvdisplay --- Logical volume --- LV Path ...
4
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2answers
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Not enough space on / to install new kernel update

During a recent update I received this: Installing: kernel-default-2.6.37.6-0.11.1 [error] Installation of kernel-default-2.6.37.6-0.11.1 failed: (with --nodeps --force) Error: Subprocess failed. ...
4
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1answer
2k views

When can Linux boot with a Read-Only Root Filesystem

I am working on a embedded Linux with u-boot as bootloader and systemd init system. The tools are limited to standard busybox. While analyzing some problems, I figured out the root filesystem is read ...
4
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1answer
3k views

What do you filter / exclude list when doing backup with rsync? [closed]

I'm trying to build a comprehensive filter / exclude file, to prevent backuping stuff that doesn't make sense do backup, such as temporary / cache data or easily recreatable files. I would appreciate ...
3
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2answers
732 views

Weird files in root directory, is secure to delete them?

What the following files means on the root directory of my Linux (Fedora 25): $ ls -la total 70 ... -rw-r--r--. 1 root root 0 Nov 22 09:28 1 -rw-r--r-- 1 root root 0 Sep 27 09:53 ....
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4answers
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Given vmlinuz and initrd.gz, how do I find out, where the kernel is going to load / (root) file system from?

I'm trying various ways of Linux installation (from iso, flash, iso on flash, kernel on flash, root FS in iso-file on flash...) and want to understand what's going on. My question is: is it possible, ...
3
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2answers
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The different uses of folders in the / (root) directory

There are a lot of folders in the / directory what do they all do? I know a few like /dev has links to devices in the system but what about /lost+found or /proc I just am curious.
3
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2answers
524 views

Where does kernel define the SD card naming index?

I'm running an embedded board that is booted from an SDCard. The location of the rootfs gets passed to the kernel via kernel parameters: Kernel command line: console=ttyS0,115200 root=/dev/mmcblk0p2 ...
3
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1answer
4k views

Login when root filesystem is full

Will I be able to login into the system if the root filesystem is 100% full? Configuration: home is not a partition but is also placed on the root (i.e. /home is a directory on the partition holding ...
3
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3answers
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Root filesystem nearly full - should I be worried?

me@netbook:~$ df -h Filesystem Size Used Avail Use% Mounted on /dev/sda5 323M 292M 15M 96% / tmpfs 5.0M 4.0K 5.0M 1% /lib/init/rw tmpfs ...
3
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1answer
57 views

Is is possible to recover from the unexpected removal of the root device?

Is it possible to recover from the entire removal and reinsertion of the root device (i.e. remounting it after reinsertion)? I'm attempting to teach a group of children about Linux via external USB ...
3
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1answer
2k views

Why is there no rootfs file system present on my system?

The linux kernel documentation claims: Rootfs is a special instance of ramfs (or tmpfs, if that's enabled), which is always present in 2.6 systems. You can't unmount rootfs … On all linux ...
3
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1answer
882 views

Does the Linux loader (ld.so) follow symlinks?

I have stumbled upon a problem by trying to move the ld.so.cache file to another location. I have tried to create a symlink for it in its previous location -- /etc/ -- but it seems that the loader ...
3
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1answer
474 views

How do you completely switch the root files system on Linux?

I am running my rootfs on a flash device (MTD device with UBIFS) - Note: it's a bitbake system so its not full-blown ubuntu or anything. I want to be able to format that device and write a new rootfs ...
3
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2answers
1k views

Effects of mounting / (filesystem root) with nodev option

I'm wondering about the effects of setting the nodev option for / mount in /etc/fstab. As I understand it, nodev prevents the interpretation of special nodes, so you can prevent rogue users or ...
3
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2answers
8k views

NFS root filesystem doesn't mount at boot

This is an embedded device with a custom kernel (see below for relevant config). It's an x86-32 machine booting like this: coreboot->uboot->linux. I can mount the NFS share in linux if I use on-...
3
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1answer
6k views

What is this file: .readahead doing in my root directory?

When I do: ls -a / on Fedora 21 there is a hidden file named: .readahead and it's 104092k What is this file?.... is it suppose to be there? I found this on google: readahead system call on wiki....
3
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1answer
203 views

Richacl invalid argument when trying to set atributes

I've compiled a kernel to use richacls, and compiled the richacl's utility, (but not the e2fsprogs). I've mounted a loop file with richacl flags /root/fs_prueba_10mb on /media/ext4_con_richacl type ...
3
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1answer
757 views

How small can an embedded Linux file system get?

We have an embedded device running the Angstrom distribution - I'm trying to pare down the root file system to as small as possible. I've started by using Narcissus to generate the file system, but ...
3
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3answers
16k views

How to switch “/” back to writable mode without reboot?

[root@SERVER .ssh]# mount|grep -i " / " /dev/mapper/rootvg-root_lv on / type ext3 (rw) [root@SERVER .ssh]# mount -o remount / mount: block device /dev/rootvg/root_lv is write-protected, mounting read-...
3
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2answers
3k views

Running QEMU with a root file system directory instead of disk image

In order to test the root file system i need to run QEMU with created disk image as root file system, the QEMU accepts -kernel which can be used for specifying kernel directly without deploying it ...
3
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3answers
65 views

Where to turn first when out of free space on Cent OS Web Server?

I am a very new Systems Administrator. I have a Windows background and am now a Jr. Systems Admin working with Cent OS 5. Our web server runs Cent OS 5 and uses PHP/MySQL for our web applications. ...
3
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1answer
1k views

How can I replace root / filesystem with another filesystem?

When the Linux kernel starts up, it uses initrd as the root / filesystem, then replaces that with a filesystem partition in fstab. Based on a test in an early init script, I want to replace that root ...
3
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0answers
562 views

Changing a root file system from initramfs to JFFS2

I am running Linux on an ARM based development board from flash memory. The rootfs is initramfs. I chose this in the configuration utility under "file system". Then I realized that I need ...
3
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0answers
441 views

LVM RAID 1 for root [closed]

I have LVM RAID 1 (not mdadm RAID 1, but exactly LVM2 RAID 1) for my root partition. I would like to make my system boot without either of the HDDs where the underlying PVs of the root LVM partition ...
2
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2answers
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How to increase the size of / with unallocated hdd space

So, I had run out of space on / (which was initially 9.3 GB). So I had some un-allocated space on my hdd (/dev/sda) that I wanted to assign to the / partition, which is also: /dev/sda1. For reference ...