[Fedora-livecd-list] my fedora 10 prophecy: the unsuckiness of liveusb persistence

[Jane Dogalt]

--- Jane Dogalt <jdogalt at yahoo.com> wrote:
 
> LiveUSB persistence as currently implemented suffers from three really nasty
> imperfections.  
> 
> 1) df -h does not really tell you how much free disk space (aka persistent
> storage) you have.  To find out how close you are to the edge of IO errors
> (aka
> disk/persistent-storage full), you actually need to pay attention to 3
> things. 
> The free space on the root filesystem, the free space in the device mapper
> snapshot overlay file, and the free space on the filesystem holding that
> file. 
> It is the minimum of those 3 values that is your real constraint.
 
minor clarification- the 3rd constraint only matters if the overlay file is a
sparse file, which, for the current typical use case on a vfat filesystem, is
not the case.

OTOH, since it is possible to (manually at the moment) increase the size of
that file while running, the free space on the filesystem that holds it is a
constraint, but just in a bit more complex way than the min(a,b,c) way I described.