[oe] base-files vs. FHS-2.3

[Phil Blundell]

On Thu, 2011-02-10 at 11:55 +0100, Steffen Sledz wrote:
> While dealing with the /var subdirs i hit some differences between Filesystem Hierarchy Standard (current FHS-2.3) and the base-files package.
> 
> One point is that /var/tmp is symlinked to volatile/tmp but according to the standard this dir contains "Temporary files *preserved between system reboots* ".
> 
> Also /var/cache is symlinked to volatile/cache but the standard describes "The data must remain valid between invocations of the application *and rebooting the system.* " what i would read in the way that /var/cache should be persistent too.
> 
> May be there are other differences.
> 
> In my opinion the symlinking in base-files is buggy and should be fixed. Or am i wrong here?

It probably would be good to have a version of base-files which was
fully FHS conformant.  But there are a significant number of OE target
systems where it is simply impossible to comply with these requirements
since there is no persistent read/write storage available: the only
choice is between flash (persistent but read-only) and ramdisk
(read-write but volatile).  

Clearly, placing /var/tmp or /var/cache in a readonly location is
unlikely to produce any useful results so linking them into volatile/ is
the least bad option in that situation.  Any change to base-files would
need to be done with some level of care in order to not break those
kinds of setups which do work today.  I guess it should be a DISTRO
decision whether or not to adhere to the FHS in this area.

p.