Lustre discuss - Nov 2009 - Slow file open close on RHEL5

Hi,

Cluster running Lustre 1.6.6
Opening and closing files takes longer on RHEL5 than on RHEL4. This is only
happens with files located on Lustre file system. To reproduce this problem
I used small c code (located on the bottom of my email).
Is this a known problem?

RH4
===real    6m24.951s
user    0m1.113s
sys     0m43.983s

real    3m21.464s
user    0m1.011s
sys     0m41.795s

real    3m15.305s
user    0m0.685s
sys     0m34.321s

real    3m52.444s
user    0m1.073s
sys     0m41.246s

RH5
===real    6m56.701s
user    0m0.602s
sys     0m52.233s

real    5m28.310s
user    0m0.613s
sys     0m48.284s

real    5m19.244s
user    0m0.555s
sys     0m44.684s

real    6m9.290s
user    0m0.613s


openclose.c
=====#include <stdio.h>
#include <stdlib.h>

int openClose() {
  FILE *fp;

  if((fp = fopen("test.dat", "w+")) == NULL) {
    printf("open error\n");
    exit(1);
  }

  if( fclose( fp )) {
    printf("close error\n");
  }

  return 0;
}

int main(void) {
  int i;
  for(i = 0; i < 300000; i++) {
    openClose();
  }
}

-- 
--
Wojciech Turek

Assistant System Manager

High Performance Computing Service
University of Cambridge
Email: wjt27 at cam.ac.uk
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