Re: tar -> unresponsive machine
Thanks to all who replied.
To answer some questions, it is a spinning hard drive, and here's
mount information:
/dev/disk/by-uuid/e3631277-c4d0-460e-a2a3-6de16013e050 on / type ext3 (rw,relatime,errors=remount-ro,barrier=1,data=ordered)
and there was plenty of free RAM as usual (the machine has 24 GB RAM),
so that I don't think Firefox was swapped out. But since Firefox often
does disk accesses (due to background tabs or whatever), it can freeze
easily. The "tar" command wasn't running as root.
And I don't have other information as I can't reproduce the problem
with the same command (and "tar" is much faster now), though I'm now
accessing the machine remotely (Firefox is no longer running...).
Now...
On 2013-02-28 16:50:32 +0000, Darac Marjal wrote:
> On Thu, Feb 28, 2013 at 11:38:23AM -0500, mark@neidorff.com wrote:
> > > Is it normal that when using the "tar" command to create a big archive,
> > > the whole machine becomes unresponsive, e.g. several dozens of seconds
> > > to do some operation (e.g. starting an xterm, or making Firefox react)?
> > >
> > > htop shows that there is still plenty of memory and atop shows nothing
> > > special, except 100% disk busy of course.
> >
> > Yes. You may want to change the "nice" level of the tar command so that
> > it doesn't take up so much disk time.
>
> "nice tar" won't actually change how heavily tar uses the disk. Instead
> try "ionice -c3 tar" (or "nice ionice -c3 tar" if you want it to use
> less[*] CPU /and/ disk).
Thanks, I didn't know ionice. It might be useful next time I
have a similar problem.
But isn't it possible to lower the priority automatically (without
an additional command like ionice) when a process takes all the
I/O resources. Perhaps this isn't clear, but what I mean is that
a process shouldn't take constantly all the resources for itself.
I expect the resources to be more or less equitably shared (which
is not what best-effort does, as described in the ionice(1) man
page).
--
Vincent Lefèvre <vincent@vinc17.net> - Web: <http://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
Reply to: