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M. Tibbits
Asked: 2010-10-13 09:15:54 +0800 CST

Is a /boot partition necessary anymore?

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A fair while ago (~ 2004) I was told to always create a separate partition for the boot directory. And since then I always have. But after reading a few questions about partitioning questions, I'm curious. Do I still need a /boot partition?

Note: If helpful, I'm dual booting (Win XP or 7) & Ubuntu 10.04. I also have one partition (using ext2/3) which I use to share files between the two operating systems.

dual-boot partitioning

3 Answers

  1. Best Answer

    If you don't use LVM, root volume encryption, software RAID, etc., and otherwise just have your root volume on a plain-jane filesystem with no intermediate layers, then you don't need it.

    Really, the most important files in booting are the kernel image (vmlinuz) and the initramfs image (initrd.img). If both of those (and the GRUB configuration files) are accessible by GRUB with no special handling, then a separate /boot volume is not necessary.

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  2. Generally speaking, unless you're dealing with encryption, or RAID, you don't need a separate /boot partition.

    That said, I occasionally find a use for adding a separate /boot partition as a FAT partition. This allows your dual-boot system to make alterations to your GRUB config, so you can create a batch file to shut down windows and alter the default menu choice so that it boots something else next. Most people don't need this, but I've had a few projects which required switching back and forth, and it allows it to be done entirely by script.

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  3. This response probably answers your question:

    Generally speaking, you shouldn't bother with a separate /home or /boot partition unless you're running multiple Linux distributions at once.

    The Ubuntu installers for both the desktop CD and server/alternate CD have the ability to install over an existing system, preserving your home directory (and the local system driectories: /usr/local, /usr/src, and /var/local). This functionality also reuses the user ID and group ID of an existing user, if it has the same username as the user you're creating during installation.

    To use this option when installing, choose the option for advanced partitioning, then select your existing / or /home partition. In the box that appears, make sure the filesystem selected matches the existing filesystem of that partition, and that the format box is not checked. Proceed as normal through the rest of the options.

    In Ubuntu 10.10 we had hoped to add an option to the installer that detected when you had an existing copy of Ubuntu installed and offered to replace it with the newer version you were attempting to install (using the aforementioned functionality behind the scenes). While it did not make the final cut, it is likely to arrive in Ubuntu 11.04.

    As for a separate /boot partition, that's a relic of hardware constraints of the past (the bootloader 1024 cylinder limit). I can think of no practical advantage a separate /boot would have on a modern system, and if not given an arguably excessive amount of space, it will potentially fill up and create problems of its own, given that Ubuntu does not automatically remove old kernels.

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