Re: Using TMPFS for /tmp and /var/run?

On 03/30/12 11:15, Steve Kargl wrote:
> On Fri, Mar 30, 2012 at 05:56:06PM +0000, Chris Rees wrote:
>> On 30 March 2012 17:31, C. P. Ghost <cpghost_at_cordula.ws> wrote:
>>> On Fri, Mar 30, 2012 at 3:18 PM,  <sthaug_at_nethelp.no> wrote:
>>>>>> However, if you always want to use tmpfs instead of stable storage,
>>>>> please do not.  Some people expect /tmp to be persistent.  This is why
>>>>> /etc/defaults/rc.conf has clear_tmp_enable="NO".  Changing this would break
>>>>> the POLA.
>>>>> This is a mistake.
>>>>>
>>>>> The default should be clear_tmp_enable="YES"
>>>>> if only to uncover those broken configurations that expect /tmp to be
>>>>> persistent.
>>>> If you want to break POLA and make a lot of people angry, sure.
>>>> Otherwise no.
>>> I couldn't agree more. Not clearing /tmp on reboot has been
>>> the norm for way too long and it is too late to change now.
>>> It's not just POLA, it also involves deleting data of unaware
>>> users, and that should be avoided.
>>>
>>> Anyone willing to change policy w.r.t. /tmp can do so on their
>>> own machines. Nothing is preventing them from doing so.
>>> But by changing defaults, one should err on the side of
>>> caution and remain conservative, IMHO.
> Well stated.
>
>> >From man hier:
>>
>> /tmp/      temporary files that are not guaranteed to persist across
>> system reboots
> There is also a difference between "not guaranteed to persist"
> and knowingly blowing the files away by explictly clearing
> /tmp.
>
> PS:
>   How many users of FreeBSD know that hier(7) exists?
>   How many new users even know about man pages?
>
man hier is a unix standard.

a new user will eventually find man pages if they're meant to, just as
small turtles will eventually find the sea...

In general you may receive some advantages by not blowing away /tmp such
as better performance in programs that cache there, but my understanding
(think historically in context of hier) is that *users* should not
expect the *admin* to not blow away /tmp for space on a multiuser
system. It might be there tomorrow, but it might not.

Many larger multiuser systems had/have such folders, as many users =
many crap files that some admin or script needs to clear to preserve
storage for things that actually need to be stored. In some cases, the
script would only clear it on Fridays in the middle of night, so
temporary files might persist from say 1 week to a few hours..."you were
warned".

Dunno, but tmpfs + unionfs for the ports tree is where it would really
be awesome!

Matt