Prebuilt distributions part 3

[This is the final article in a three part series. Read part 1 and part 2.]
In this part I was going to discuss the different installation options, and I’ll give a quick introduction to each at the end. But you know? What I really need is this tool:

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| Rich’s Amazing Bug Environment [...]

libguestfs architecture ASCII art

There was a little bit of confusion about how exactly libguestfs works, so I drew the architecture diagram in wonderful ASCII art … This is what happens when you type guestfish -a disk.img …

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New tool: virt-list-filesystems

$ virt-list-filesystems Debian5×64.img
/dev/debian5×64/home
/dev/debian5×64/root
/dev/debian5×64/tmp
/dev/debian5×64/usr
/dev/debian5×64/var
/dev/sda1

You can also augment this tool with the -a and -l options. The -a option tells it to list swap partitions too. The -l option tells it to show the filesystem type on each partition that was found:

$ virt-list-filesystems -a -l Fedora12.img
/dev/sda1 ext4
/dev/vg_f12×64/lv_root ext4
/dev/vg_f12×64/lv_swap swap

While this is a fairly simple tool, [...]

Prebuilt distributions part 2

In part 1 I discussed how these days Linux Live CDs usually come with a prebuilt disk image of the distro which is simply copied over to the hard disk during installation. (The “old” method was to rpm/dpkg-install the packages which is much more time-consuming). However my first test wasn’t very successful because [...]

Prebuilt distributions part 1

Previously I took a look at unpacking Fedora and Ubuntu live CDs to find out what’s inside them and to ask the question can we use the prebuilt filesystem image that these live CDs contain to quickly create a Fedora or Ubuntu “all-defaults” virtual machine?
This is my first attempt, and it’s not successful, but it [...]

Looking closer at Fedora, Ubuntu live CDs

Previously I’ve shown you can use guestfish to unpack a Fedora live CD.
I’m interested in whether we can use the contents of these live CDs to mass-install operating systems using libguestfs.
If you imagine that you go through an “all defaults” install of say Fedora or Ubuntu to a new virtual machine, then when you end [...]

mkfs compared on different filesystems

How long does it take to mkfs a 10GB disk with all the different filesystems out there?
See my test results here using the new guestfish sparse / filesystem support. btrfs is “best” and ext3 comes off “worst”.
As a test this is interesting, but it’s not that relevant for most users — they will be [...]

Filesystem metadata overhead

Which filesystems have the largest metadata overhead[1]? We can find out using guestfish sparse file support and a short shell script:

#!/bin/sh -

guestfish=fish/guestfish
testimg=/mnt/tmp/test/test.img
size=1G

for fstype in ext2 ext3 ext4 xfs ntfs msdos ; do
$guestfish <<EOF
sparse $testimg $size
run
[...]

Petabytes? Exabytes? Why not

Frankly I’m a bit surprised this works …

$ guestfish

Welcome to guestfish, the libguestfs filesystem interactive shell for
editing virtual machine filesystems.

Type: ‘help’ for help with commands
‘quit’ to quit the shell

><fs> sparse /mnt/tmp/test/test.img 1P
><fs> run
><fs> blockdev-getsize64 /dev/vda
1125899906842624

$ guestfish

Welcome to guestfish, the libguestfs filesystem interactive shell for
editing virtual machine filesystems.

Type: [...]

Terabyte virtual disks

This is fun. I added a new command to guestfish which lets you create sparse disk files. This makes it really easy to test out the limits of partitions and Linux filesystems.
Starting modestly, I tried a 1 terabyte disk:

$ guestfish

Welcome to guestfish, the libguestfs filesystem interactive shell for
editing virtual machine filesystems.

Type: ‘help’ for [...]