Dual booting Windows 8 and Arch Linux with UEFI

Question

Hi all!
I'm trying to install Arch Linux on my computer where I already have Windows 8, and I'm getting a little stuck when it comes to the partitioning.
Following the beginner's guide and the method here: https://wiki.archlinux.org/index.php/Un … n_in_Linux for setting up the partitions properly, regarding UEFI. My problem is that when using cgdisk to set up a new EFI system partition (ef00), I get an error message when trying to write the partition table (just saying that something went wrong). I figure the problem is that I already have a partition like this (correct me if I'm wrong), but it really looks like it succeded (see info below). So my question is: How do I preceed to keep my Windows 8 installation happy, but installing Arch? Do I remove the old EFI system partition and create a new one, or is there some method that allows me to edit the already existing one, to allow me to dual boot Windows 8 and Arch?
My partition table now looks like this:
Part. # Size Partition Type Partition Name
1007KB free space
1 500MB Windows RE Basic data partition
2 300MB EFI System EFI system partition (this one was already present on my system)
3 128MB Microsoft reserved Microsoft reserved partition
4 63.5GB Microsoft basic data Basic data partition
8 512MB EFI System EFI System partition (this is the one I tried to create when I got the error message)
5 29.5GB Linux filesystem Arch (this is where I was going to put my Arch installation)
6 22GB Windows RE Basic data partition
7 1024MB Windows RE Basic data partition
615KB free space
Just for the record; I only created partition #8 and #5.
Any help is appreciated! And sorry for beeing a total noob, but I really suck at this.

Answer 1

sudo make sandwich wrote:If it is possible to share ESP between OSes, how do I do this (would it be sufficent to follow this section: https://wiki.archlinux.org/index.php/Beginners'_Guide#For_UEFI_motherboards)?
There's really very little to do to share an ESP between OSes. Most OS installers will auto-detect the ESP and use it. Problem solved. For Arch it may be a bit more effort just because Arch uses a more hands-on installation process, but I've only done a couple of Arch installations, and the last one was several months ago, so I don't recall the details clearly enough to comment.
And how big will the partition need to be? The beginner's guide says 512MB or higher.
I don't know what was in the mind of the author, but my guess is that's because that's roughly the cutoff point where mkdosfs starts creating FAT32 by default rather than FAT16. The ESP is officially supposed to be FAT32, not FAT16, although FAT16 usually works OK. It's also possible to create FAT32 on smaller partitions by using an explicit option to mkdosfs ("-F 32").
The optimal size of the ESP depends on the files stored on it. If you don't store your Linux kernels, something as small as 100MiB is usually adequate; but a few Linux kernels and their initrd files can consume twice that amount. My own recommendation is for the ESP to be 200-500MiB.
The only error message I got from cgdisk is "Problem saving data! Your partition table may be damaged!", however booting Windows again works fine. Parted did not complain about antything.
Use the "verify" function in cgdisk. That will reveal any problems with the data structures. If a verify turns up OK, then that means that cgdisk ran into some sort of disk problem. Running gdisk rather than cgdisk and using the gdisk "w" option (without making any changes) may produce a more helpful error message.