[buildd-tools-devel] Bug#563957: schroot should support aufs for chroots

[Julian Andres Klode]

Package: schroot
Severity: wishlist

It seems that aufs would be a good idea to support in schroot. It's faster
and more efficient than LVM; and should be equally reliable. We are shipping
it in our kernel (mostly because Debian Live needs it) and it just works.

For it to work you need 3 directories:

	a) the directory containing the chroot
	b) an empty directory storing session data (the overlay)
	c) the directory where the union is mounted.

Example:
	/path/to/chroot/ => the base chroot
	/path/to/session-data/ => modified and new files and removals
	/path/to/session/ => the union of chroot + session-data

The command:
  mount -t aufs -o br=/path/to/session-data:/path/to/chroot none /path/to/session

would create an overlay which has all the files from /path/to/chroot, but
writes all changes into /path/to/session-data. Once /path/to/session is unmounted,
it will only contain the differences to /path/to/chroot anymore.

/path/to/session-data/ could also be equal to /path/to/session/ in which case
it contains the union while mounted and once unmounted it only contains the
differences.

-- System Information:
Debian Release: lenny/sid
  APT prefers unstable
  APT policy: (990, 'unstable'), (350, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.32-trunk-amd64 (SMP w/2 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages schroot depends on:
ii  libboost-filesystem1.40.0     1.40.0-5   filesystem operations (portable pa
pn  libboost-program-options1.40. <none>     (no description available)
pn  libboost-regex1.40.0          <none>     (no description available)
ii  libboost-system1.40.0         1.40.0-5   Operating system (e.g. diagnostics
ii  libc6                         2.10.2-3   Embedded GNU C Library: Shared lib
ii  libgcc1                       1:4.4.2-8  GCC support library
pn  liblockdev1                   <none>     (no description available)
ii  libpam0g                      1.1.0-4    Pluggable Authentication Modules l
ii  libstdc++6                    4.4.2-8    The GNU Standard C++ Library v3
ii  libuuid1                      2.16.2-0   Universally Unique ID library
pn  schroot-common                <none>     (no description available)

schroot recommends no packages.

Versions of packages schroot suggests:
ii  debootstrap                   1.0.20     Bootstrap a basic Debian system
pn  lvm2                          <none>     (no description available)
ii  unzip                         6.0-1      De-archiver for .zip files

-- 
Julian Andres Klode  - Debian Developer, Ubuntu Member

See http://wiki.debian.org/JulianAndresKlode and http://jak-linux.org/.
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