Re: /tmp as tmpfs and consequence for imaging software
On Sun, Nov 13, 2011 at 12:04 PM, Lars Wirzenius <liw@liw.fi> wrote:
> On Sun, Nov 13, 2011 at 06:30:27PM +0800, Thomas Goirand wrote:
>> Agreed. Anyway, I'd be happy to have, by policy, some hard limits
>> We can discuss of a tolerable size, like 100M? Anyway, anything
>> bigger than 512 MB is obviously abusing /tmp, IMHO. But if we're
>> to have /tmp using tmpfs by default, it becomes really important
>> to have such policy.
>
> Greetings from the real world.
>
> There are systems where /tmp is on a real disk, and has terabytes
> of free space, and it's totally OK to use most of that, temporarily.
> I have one such system for running benchmarks of my backup program.
> Having a Debian policy that programs are not allowed to use more
> than 100 megabytes of temporary files would make my benchmarks
> useless.
>
> There are systems where /tmp is on a flash unit, and the total amount
> of flash and RAM in the system is less than 100 megabytes. I have one,
> it runs very well as a firewall. A Debian policy that requires a
> program to be able to use at least 100 megs of temporary file space
> would make it hard to use Debian on highly constrained systems.
>
> A fixed policy is going to interact badly with real systems and
> per-site decisions about, say, disk partitioning and provisioining
> of RAM for various purposes.
>
> The proper policy, IMHO, is that a) all software that uses temporary
> files should obey TMPDIR if set (and fall back on /tmp if not)
> and b) all software must deal with out-of-disk-space errors in a
> sensible way (where the exact details may depend on the software).
>
> It is then a sysadmin decision to setup /tmp or TMPDIR properly
> so there's enough free space for temporary files for the software
> they use. Debian should provide sensible defaults, but it's not
> possible to pick defaults that are optimal for everyone, in
> this situation. Given that MySQL, scientific software, and such
> systems are mostly run on systems that have sysadmins, and desktops
> are run by people who do not, it's sensible to favor the desktop
> case by default.
In my uni sysadmin said: we use distribution default by default, if
you want to change default fill a complain. It take about 3 month to
get some simple change from default like activing transparent hugpage
for hpc. I know it is crappy but it is also real world. Do not think
that sysadmin are competent.
To the contrary they care less about desktop because you could only
hit your own system. So you have modification in less than two days.
Bastien
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