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11
votes
2answers
2k views

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 ...
7
votes
3answers
964 views

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! 3 'applications', so to speak, are required to boot a funcitonal distro of Linux: Bootloader - For embedded typically that's U-Boot, ...
7
votes
3answers
1k views

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 ...
7
votes
1answer
846 views

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 ...
5
votes
1answer
189 views

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 ...
4
votes
2answers
2k views

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 ...
4
votes
2answers
1k views

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 ...
4
votes
5answers
3k views

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 ...
4
votes
2answers
2k views

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
votes
1answer
3k views

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. ...
3
votes
3answers
3k views

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
votes
1answer
436 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
votes
1answer
33 views

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

As it says on the tin, is it possible to recover from the entire removal and reinsertion of the root device (I.E. remounting it after reinsertion)? The reason I'm asking is I'm attempting to teach a ...
3
votes
1answer
889 views

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 ...
3
votes
1answer
112 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
votes
1answer
1k views

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 ...
3
votes
1answer
133 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
votes
1answer
1k 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
votes
1answer
435 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
votes
0answers
163 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
votes
0answers
168 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
votes
2answers
280 views

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 ...
2
votes
3answers
926 views

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 ...
2
votes
3answers
989 views

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 ...
2
votes
1answer
41 views

/bypass folder on ArchBang - safe to delete?

Anyone know what is this folder for, and if it's safe to delete it? It's an ArchBang box, and this folder was there ever since install. I'm not really sure if it's just some junk left after ...
2
votes
3answers
987 views

clone root directory tree using busybox

I have an TI DaVinci-based (ARM architecture kin to OMAP) system which netboots using TFTP and NFS-mounted root filesystem, and am trying to make it boot standalone without a netboot server. The ...
2
votes
1answer
46 views

What can I (not) shred from root while it is mounted?

I am performing a test migration from old server to new one. Part of the procedure involves cleaning up the old server of any traces of passwords, php scripts and custom configurations while remotely ...
2
votes
1answer
63 views

Booting Linux minimally

I am trying to boot just linux itself. It's mostly for the learning experience. I got a small HDD with only one ext4 partition looking like this: /bin/bash /dev/console /boot/vmlinuz ...
2
votes
2answers
768 views

Adding files to Linux readonly-root

I've a netboot Linux server where the the /root is mounted as readonly. # Set to 'yes' to mount the system filesystems read-only. READONLY=yes # Set to 'yes' to mount various temporary state as ...
2
votes
0answers
33 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 ...
2
votes
1answer
89 views

Free-ing up unused space on a partition that is unaccessible after a mount

Originally I had a 50GB disk where the root / was mounted to a 6 GB partition on it. The partition was running out of room so I created a second partition with the rest of the free space (44 GB). ...
2
votes
0answers
41 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 ...
2
votes
1answer
780 views

How can I resize my encrypted root and home partitions, to give root more space?

I need to enlarge my / (root) partition, I have a lot of space on my /home partition so how can I do this? The drive is encrypted with LUKS. My system is Fedora 20. I have another thread here which ...
2
votes
0answers
155 views

What's status of btrfs as root fs? [closed]

What is the current status of btrfs being the root filesystem including /boot; meaning that you do not need to create a separate /boot partition. I ask because I noticed on Debian 7 you cannot setup ...
2
votes
0answers
183 views

What changed between kernels 3.7 and 3.9 that affects LVM/RAID root file systems?

I'm trying to fix a (very messy) system that the user hosed by running a kernel upgrade from 3.7.10 to 3.9.6. the root file system is on an LVM volume on top of a software RAID array. The boot manager ...
2
votes
1answer
108 views

Flashing rootfs on Embedded Linux with Limited RAM

I'm fairly new to the embedded world, so forgive me if this seems obvious. I'm working on a board based off of the AT91SAM9260. I have 256MB of flash and 64MB of RAM. The current setup flashes two ...
1
vote
2answers
8k views

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 ...
1
vote
1answer
33 views

How to transfer a rootfs folder?

I just created a rootfs with debootstrap in a Debian Jessie VirtualBox VM. Now I would like to transfer this to the host, by first compressing the directory to a tar archive, so I can upload it and ...
1
vote
2answers
459 views

Moved some files unable to use mv now

I accidently used mv mymods /* * . Now i am unable to undo it or either use any command. How do i fix that? I was in directory name /home/nginx/crap [root@somehost /home/nginx/crap]# mv mymods /* * ...
1
vote
2answers
34 views

Create mount points automatically in /mnt, even though / is read-only

I have a requirement of changing my root partition to Readonly. After changing / to readonly in /etc/fstab, I rebooted the system. Mount points of USB devices is /mnt. But after above changes USB ...
1
vote
1answer
73 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 ...
1
vote
1answer
174 views

WARNING: at kernel/irq/handle.c - after changing rootfs, but why?

today I changed from an image with initramfs to an image with separate kernel and rootfs. Theses images are used for an Embedded System (ARM9 SAM9G25), that is runnging with an Linux 2.6.39. During ...
1
vote
1answer
84 views

What is the correct approach to reduce the size of the rootfs.cpio?

I use cpio -idv <rootfs to extract what all is inside my rootfs.cpio file. Following are the contents of a defualt rootfs.cpio that I get after compiling petalinux: [root@xilinx ourput]# ...
1
vote
1answer
485 views

Difference between initramfs.cpio and rootfs.cpio

What are the differnces between the two? Can I just use initramfs.cpio or do I need to use both? Actually my rootfs.cpio file is 7 Mb and initramfs.cpio is just 0.5mb, so I was thinking if I can use ...
1
vote
0answers
11 views

Mounting real rootfs after initial booting using initrd

I'm booting kernel with root=/dev/ram0 on a embedded environment. After initial booting, how can I mount real rootfs present at /dev/mtd3 and make it as the only rootfs. I'm using root=/dev/ram0 ...
1
vote
1answer
29 views

Fault-tolerant iSCSI root fs for Linux

I am in the process of moving some Linux servers onto a virtualized environment with their filesystems mounted from LVM volumes, which are in turn hosted on a remote NAS via iSCSI. I am able to start ...
1
vote
1answer
81 views

At Backup, when would the filesystems inode numbers matter?

background: Being somewhat of a coward I have up to now dd whole filesystems for backup. Major drawback has become the excessive use of memory for those complete backups (which unfortunatelly also ...
1
vote
0answers
88 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 ...
1
vote
0answers
135 views

Encrypt root file system and decrypt using U-Boot with key stored in FPGA

We are using Cyclone V, which essentially is a SOC comprised of FPGA + ARM core. Is it possible to encrypt the root file system and decrypt it by using U-Boot with a key which is located in the FPGA?
1
vote
0answers
256 views

Mounting root filesystem while booting through network

I have two systems, let say one is the server and the other is the client. I want to load kernel image from the server to the client through the network. I used dhcp (isc-dhcp-server) and tftp ...