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Splitted live-snapshot patches + some comments on snapshot internals

On Saturday 07 June 2008 17:01:25 Otavio Salvador wrote:

> > I split the 1 missing all-in-one patch to 6 finer grained patches without
> > changing code style.

> > http://git.debian.org/?p=users/mammadori-guest/live-initramfs.git;a=summa
> >ry

> The change 81894c09d48292cf75ff619f4a4dd196ea935387 is wrong. It needs
> to be split in two patches.
> One for PROGRAM_NAME change and other for the others.

I removed the PROGRAM_NAME change directly.

> The change 14b8162451a4bc566d98611f169844094282d2c5 has a useless
> comment (probably forgotten) # Some defaults.

Done both, also splitted the manpage update in their relative commits.

> All others looks OK for me.

I've added 2 small ones which fixes 1 missing declared feature and a minor 
unnecessary information during automatic resync.

Let's see if now they could fit also Daniel's needs.

And now, for something completely RELATED:

If I'll can I'll try to add a cpio.lzo target before the freeze; it is really 
useful for slow systems since lzo is a very fast compression library, although 
it is not a good candidate for replacing the default "cpio.gz" since the 
latter is supported by busybox and klibc without external dependencies.

The squashfs target is meant to be built in order to put it side the main 
filesystem.squashfs on CDRW multisession open media, here an helper to reburn 
just this snapshot would be great.

The latter ext2 is meant to ease the creation of the "Cow" persistent media 
instead of using tmpfs which is the original casper solution for persistence 
from ubuntu. But this way has proven to be slow in practice, although is the 
most "unplug power cord" friendly one.

Both squashfs and ext2/3 target was only tested by me 2 years ago and worked 


Now cpio.gz is the only guaranteed target (fully tested by me on iso media  
with the /etc/live-snapshot.list option).

All other targets will fail until "/live/cow" will became visible again (this 
bug is related with busybox/klibc recent mount changing, should be like the --
move support btw).

Squashfs support at boot was also added to support modules and hence the 
concept in live-package (at that time) to build differents squashfs 
incrementally, designed like it shoulded mounting at build time (now by live-
helper) the chroot from the previous squashfs sets and a writable dir as the 
cow, source of the new squashfs module block.

But this could be a nice thing to have in lenny+1 since I just wrote a concept 
for a old build system.

A little brainstorming could help here to provide the most useful and flexible 
"writeable" on a read-only media option to our users. There are many bugs and 
missing features now, like deleting files (which needs .wh. whiteouts 
internals of aufs/unionfs, or implementing custom mass delete at boot) or 
copying only file which are really changed to save spaces.

Any wishlist or ideas on snapshot/persistent topic here?


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