[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: /tmp as tmpfs and consequence for imaging software

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

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.

Freedom-based blog/wiki/web hosting: http://www.branchable.com/

Attachment: signature.asc
Description: Digital signature

Reply to: