Pilgrim, kadischi, and stateless (was Re: [Fedora-livecd-list] pilgrim livecd work)

[David Zeuthen]

On Thu, 2006-09-21 at 20:52 -0700, Toshio Kuratomi wrote:
> Multiple writable fs's should be okay as long as the merged filesystem
> only writes to a single fs.  Say the last writable fs added to the
> stack.  Allowing writes to several layers in the stack is... not
> something I want to attempt :-)  Maybe you could create a simple unionfs
> using fuse, although it might sacrifice performance for convenience....

There appears to be at least two of them

 http://funionfs.apiou.org/?lng=en
 http://podgorny.cz/moin/UnionFsFuse

Not sure whether this 

 a) works with rootfs e.g. "/"; (the former claims it doesn't)

 b) whether it requires us to pull in this user space code in the
    initramfs (which is entirely possible) or whether we can do
    a trick to remount rootfs later

 c) provides adequate performance

Btw, I'm planning to include the http://www.bootchart.org/ stuff [1] in
the livecd; ideally we'd just turn it on by passing 'bootchart' via
grub. Then it's much easy to evaluate c) and also other stuff. TBH, I
haven't starting comparing performance of the pilgrim livecd's against
other livecd's yet...

Then again, this is only really interesting for the persistent livecd
use-case and I'm not sure how important that is at this point.

    David

[1] : Does anyone know if this is in Extras? Can't seem to find it.