Image Format

Version 4 (Nikos Skalkotos, 11/23/2011 02:17 pm) → Version 5/39 (Nikos Skalkotos, 11/23/2011 04:13 pm)

h1. Image Format

Right now we support 4 different types of images:
* extdump
* ntfsdump
* diskdump
* custom

h2. extdump & ntfsdump

Those two formats are raw copies (using dd) of partitions hosting Linux systems on ext{2,3,4} and Windows systems on ntfs filesystems respectively.

Partitions hosting a Windows or Linux linux system that are suitable for dumping should have the following properties:
* Be the first partition in the filesystem
* The OS they host should shall not depend on any other partitions
* Start at sector 2048
* Have a bootloader installed in the partition
* Have the root device named through UUID in /etc/fstab specified in a persistent way, using UUID or LABEL (for extdump only)

h3. Known Issues

* For linux systems, having grub installed in the partition is fragile and things can go wrong when resizing the partitions, especially when shrinking.
* Swap space is not supported.
* More complicated partition schemes are not supported.

h2. diskdump

Diskdump is a newer format that overcomes most of the aforementioned issues. This format is a raw copy (dd) of a whole disk, instead of a partition. issues

This design has the following benefits:
* Swap partitions are supported
* The system may use multiple partitions:
** dedicated partitions for /boot, /home etc in linux
** system and boot partition in Windows
* There are no restrictions on partitions starting sectors

Although diskdump is a lot more flexible that the older formats, there are still some rules to follow:
* All devices in fstab should be specified by persistent names (UUID or LABEL)
* LVMs and extended partitions should be avoided