[LEDE-DEV] persistent /var (or /data)?

[Alberto Bursi]

On 09/23/2016 07:52 PM, Daniel Golle wrote:
> On Fri, Sep 23, 2016 at 07:43:59PM +0200, Bastian Bittorf wrote:
>> * Daniel Golle <daniel at makrotopia.org> [23.09.2016 19:19]:
>>
>> [...]
>>
>>> On Android and other embedded systems, this whole issue is solved by
>>> having a designated volume mounted on /data, usually backed by a
>>> partition on an sdcard or the like.
>>>
>>> Similarly, on systems with block or large (SLC!) NAND storage we
>>> could introduce an additional partition/volume mounted on /data and
>>> just not have that directory on systems without any storage options.
>> [...]
>>
>> in our systems we introduced 2 new global varnames:
>>
>> $TMPDIR (like 'temp')
>> $PERMDIR (like 'permanent')
> That's kinda the idea. How do you know during runtime if $PERMDIR was
> successfully mounted, ie. if a service which requires permanent storage
> should be started?

AFAIK Only sane way is adding these options in the packaging, so you 
will know on install time what packages will have files (and what files) 
that should always stay in /tmp, what have files that can stay in /tmp 
but would be cooler to keep them on /data, or what packages MUST keep 
their files in /data.

-Alberto