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Re: Moving /tmp to tmpfs makes it useless



On 25/05/12 12:14, Henrique de Moraes Holschuh wrote:
> On Fri, 25 May 2012, Thomas Goirand wrote:
>> for small files, and in that case, it's faster. In reality, it's
>> not that much faster, thanks to Linux caching of the filesystem,
> 
> Under heavy filesystem IO load, yes it is.  By several orders of magnitude.
> 
This is a corner case.

Defaults should be sane for most of the cases, and not for corner cases.
Also defaults should prioritize stability (and non-breakage) over
performance.

With "tmpfs on /tmp" you are breaking many applications that assume that
they have enough space to write on /tmp like the flash player ( see
Debian bug #666096 ) or cdrecord software ( see #665634 ).

>> the point. Maybe we should add a /small-files-on-tmpfs (choose
>> a better name, of course...) folder so that apps know what to do,
>> that'd be a lot more graceful than just switching to whole /tmp
>> to tmpfs without any app knowing about it.
> 
> Nice idea, but it would be worthless.
> 
> In fact it is the other way.  We have /var/tmp for the large file since
> about forever, and important platforms that have /tmp in memory since the
> early 2000's (Solaris)....
> 

They did it, because their native file system (UFS) was very slow.
Even linux ext2 was faster than Solaris tmpfs!! [1]

> And that STILL wasn't enough for people to not screw it up and dump large
> files in /tmp.
> 

The FHS [2] does not define *nothing* about the size of /tmp or
/var/tmp. It *only* says that programs using files under /tmp must not
assume that this files are preserved between invocations of the program


So please, *stop* saying that /tmp should be only for small files
because this is simply *not* *true*. It is *not* defined on any standard
that files on /tmp should be small. Period.


Regards!
--------

[1]
http://marc.info/?l=linux-kernel&m=90222140834090&w=2
http://marc.info/?t=90223928400001
[2]
http://www.pathname.com/fhs/pub/fhs-2.3.html#TMPTEMPORARYFILES
-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Carlos Alberto Lopez Perez                           http://neutrino.es
Igalia - Free Software Engineering                http://www.igalia.com
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