Re: how to increase space for tmpfs /tmp



Am Donnerstag, 29. März 2012 schrieb Javier Vasquez:
So yes, one needs to be careful, not to oversize your tmpfs. That's
completely true, but the limit is not physical RAM, it is actually
RAM+Swap, as I mentioned before.

On this thread, it is asked about how to got with huge files to be
handled by tmpfs, well, debian still gives the option to set /tmp as a
regular partition for example, but if you also have enough swap space,
then by setting the right tmpfs size, you can still get away with it
through tmpfs. Actually in this case I suggested 2g or even 3g for
tmpfs, which was discarded because it sounded dangerous at first by
looking only at RAM, and not considering at all the available swap,
which in my mind and experience is a mistake.

Only thing with this could be that swapping in my observation has a quite
high I/O priority. When I have my students in my Linux performance
analysis & tuning trainings test to allocate lots of memory, more than
physical RAM the Linux machine responds quite jerky and I get much higher
latencies.

Thus when I access something from a tmpfs that it is swap I might have
higher latency for my usual workloads. And it might even be faster to just
read it from disk. But then everything from the tmpfs that is in physical
RAM is accessed way faster as from disk as well. I.e. I let the kernel
decide and autotune for my workload.

IMHO it might be better to size / use tmpfs in a way that only uses swap
rarely or seldom. But your mileage may vary.

Or it might be wise to reduce the priority of swapping for tmpfs
filesystem, but I am not sure whether that would be feasible to implement
to the kernel.

--
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7


--
To UNSUBSCRIBE, email to debian-user-REQUEST@xxxxxxxxxxxxxxxx
with a subject of "unsubscribe". Trouble? Contact listmaster@xxxxxxxxxxxxxxxx
Archive: http://lists.debian.org/201204042033.44628.Martin@xxxxxxxxxxxx



Relevant Pages

  • Re: /tmp is too small
    ... Increase your swap to 4GB -- even if you plan never to swap. ... space will be available to act as backing store for tmpfs. ... RAM + SWAP. ... To UNSUBSCRIBE, email to debian-user-REQUEST@xxxxxxxxxxxxxxxx ...
    (Debian-User)
  • Re: / almost full
    ... it being used as tmpfs; ... Swap is not mandatory. ... If you think you will need some, add equal to system ram, but I don't ... To UNSUBSCRIBE, email to debian-user-REQUEST@xxxxxxxxxxxxxxxx ...
    (Debian-User)
  • Re: HDD powersaving at music playing.
    ... If you have enough unused ram they will stay in memory. ... (not tmpfs, it also uses swap) ... I have no swap, RAM only. ... To UNSUBSCRIBE, email to debian-user-REQUEST@xxxxxxxxxxxxxxxx ...
    (Debian-User)
  • Re: how to increase space for tmpfs /tmp
    ... ALL of the tmpfs space. ... the percentage is with respect to RAM. ... in swap same amount of RAM). ... To UNSUBSCRIBE, email to debian-user-REQUEST@xxxxxxxxxxxxxxxx ...
    (Debian-User)
  • tmpfs and DVD writing, and multi-device swap
    ... I'm going to be installing Fedora 6 on a new PC I just built, and I'm considering using tmpfs for /tmp. ... The thing is, I only have 4GB of physical RAM, and the docs I found say that the default size for a tmpfs instance is half of physical RAM and that oversizing can lead to deadlocking the out-of-memory handler. ... Also, if I split my swap space across three drives with equal priority, and one drive goes down, will the system crash? ...
    (comp.os.linux.questions)