Filesystem overlay ?

[Dave Stubbs]

William Park wrote:

>I would appreciate if someone with better memory can kick me in the
>right direction... 
>
>Suppose you have read-only filesystem (eg. CD-ROM) mounted on /var.  Is
>there some overlay feature that you can enable (in kernel or
>filesystem), so that /var appears to be read-write while the system is
>on.  But, when you reboot, you're back to original /var content.
>
>I've remember something like this is possible in 2.6.  But, name or
>keyword escapes me.
>
>  
>
Hi William,

Well, there's a few:
  - unionfs - http://www.fsl.cs.sunysb.edu/project-unionfs.html
  - ovlfs - http://ovlfs.sourceforge.net/ (this one appears to be dead, 
but slax uses it)
  - translucency - http://sourceforge.net/projects/translucency/
  - mini_fo - can't find homepage, but Morphix seems to run on this
  - cowloop - http://www.atconsultancy.nl/cowloop/

Apparently there are even more.  I found these by lurking in the slax 
forums, watching threads between the Slax guy and people with all kinds 
of suggestions to replace ovlfs.  Slax is a bootable CD Linux Distro 
based on Slackware - you'd like it :-)  Apparently even lvm could be 
made to do this, but that might be quite complex.

Dave...
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