Unix and Linux Stack Exchange
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Questions tagged [initrd]

initrd is a method for loading a temporary file system into memory, during the process of booting the Linux kernel.

The initrd is mounted prior to the availability of the "real" root file system. In the case of embedded systems, the initrd is the file system image. See also , a newer similar facility.

Usually it will contain the minimal utilities needed for providing access to storage devices and filesystem.

For more information, check the article Linux initial RAM disk (initrd) overview.

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Why is it that my initrd only has one directory, namely, 'kernel'?

I'm using debian live-build to work on a bootable system. By the end of the process i get the typical files used to boot a live system: a squashfs file, some GRUB modules and config files, and an initrd.img file. I can boot just fine using those…
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What is the equivalent of mkinitcpio.conf on debian?

I want to review that the hooks used to build the initrd.img are correct in my debian but I fail to find the /etc/mkinitcpio.conf file like the one in Archlinux, what is the equivalent of this file in debian and how do I rebuild the initrd.img once…
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How does Linux load the 'initrd' image?

I've been trying to understand the booting process, but there's just one thing that is going over my head.. As soon as the Linux kernel has been booted and the root file system (/) mounted, programs can be run and further kernel modules can be…
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Is the entire kernel loaded into memory on boot?

I read through this popular IBM doc (I see it referred quite often on the web) explaining the function of the initial RAM disk. I hit a wall in conceptualizing how this works though. In the doc it says The boot loader, such as GRUB, identifies the…
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Is it possible to put root in LVM without using initrd?

I have just set up a Gentoo base system (which means I can boot and log in and do stuff with it now). My root partition is in an LVM2 virtual group (with a separated /boot partition). In order to boot I need to pass the parameters below to the…
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Linux kernel is not finding the initrd correctly

I had compiled a linux kernel and I wanted to debug it in QEMU. I created a file to boot from by doing the commands $ qemu-img create -f raw disk.img 200M $ mkfs.ext2 -F disk.img # mkdir /mnt/rootfs # mount -o loop disk.img /mnt/rootfs Then I did…
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Why is my initial ramdisk so big?

I'm running Ubuntu 11.10, which came with kernel version 3.0.0-14. I downloaded and built a kernel from the 3.1.0 branch. After installing the new kernel, I see that my /boot/initrd.img-3.1.0 file is HUGE. It's 114MB, while my…
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How can I force a Ubuntu kernel to fail mounting / and drop into the initramfs rescue shell?

I am trying to customize the initramfs rescue environment and would like to force the kernel to fail mounting / and drop into the (initramfs) rescue shell, as opposed to single user mode. How can I do that? NB: I know how to hook into…
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How to populate /dev directory when building my own initrd?

I am trying to learn stuff about initrd. I have followed this tutorial to build my own initrd from scratch, and I installed busybox on it. Then I made an .iso from it with isolinux, so I could test it in virtualbox. It works great! I have the basic…
Carlito
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vmlinuz and initrd not found after building the kernel?

After configuring and building the kernel using make, why don't I have vmlinuz--default.img and initrd-.img, but only got a huge vmlinux binary (~150MB)?
Amumu
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Is Ramdisk and initrd the same?

While reading through the kernel documentation on ramdisk in ramfs-rootfs-initramfs.txt i was having a doubt like the ramdisk explained there is same as the initrd features described in the post at the-difference-between-initrd-and-initramfs. …
Navaneeth Sen
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Ubuntu: How do the md devices get assembled at bootup?

How do the md devices get assembled at bootup in Ubuntu? Is /etc/mdadm/mdadm.conf truly the relevant factor here? My mdadm.conf is sound and I checked that while I was in the rescue CD environment. When running mdadm -A --scan it finds and assigns…
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Ubuntu 21.04 hangs at "loading initial ramdisk" after kernel update with LUKS

I've reproduced this twice from a fresh install - the setup initially works fine, but when a kernel update is applied, the system hangs on reboot. Selecting the older kernel I have available from GRUB works fine. System details: XPS 13…
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Add Apache to Ubuntu's startup

I'm currently learning the Linux environment, and decided to manually install the Apache server. For educational purposes, I've compiled it into: /server/apache The http.conf location is configured correctly. It works -- I can open up a browser and…
Stann
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Repack the filesystem image from vmlinux.bin (embedded initramfs) without rebuilding?

In How do I extract the filesystem image from vmlinux.bin? and https://wiki.gentoo.org/wiki/Custom_Initramfs#Salvaging methods are presented for getting and unpacking an embedded initramfs/initrd included in the kernel image. Now I would like to…
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