[Lustre-discuss] Lustre slow file open close on RHEL5

[Wojciech Turek]

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? I will be grateful for any suggestions.

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
Tel: (+)44 1223 763517
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