Creating lots of files on Hammer

Michael Neumann mneumann at ntecs.de
Thu Jul 10 16:15:25 PDT 2008


Matthew Dillon wrote:
:Hi,
:
:I wrote a script that generates 1 million files in one directory on the
:hammer filesystem. The first 100k are created very quickly, then it
:starts to get less predictive. It stops completely after creating 836k
:files. I can still ping the machine, but I can't ssh into it any more.
:It's a head-less system so I can tell what is going on exactly.
:
:I'm using the attached C file like this:
:
:   cr 1000000 test
:
:Regards,
:
:   Michael
     Oooh, nice test.  Mine got to 389000 before it deadlocked in
     the buffer cache.
     I'll be able to get this fixed today.  It looks like a simple
     issue.
Commit 61/A fixes the problem. But now, after creating around 3 million
files and doing a "cpdup /usr/pkgsrc /hammer/pkgsrc", running "make
head-src-cvsup" turned out to be extremely slow (actually it was the
"cvs update" part). Then I did a "rm -rf
/hammer/dir-with-a-million-files" and hammer finally died :) It probably
core dumped :(
I can try to reproduce it tomorrow with a display connected to it.

Another thing I noticed is that when there is a lot of file system
activity, other user processes are slowed down a lot (maybe they are
just blocked on a condition). At least that's how it feels.
Regards,

  Michael





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