Can you check if you have readahead enabled? http://manual.lustre.org/manual/LustreManual16_HTML/LustreProc.html#50557055_78950
This could probably be your cause. On Thu, Nov 12, 2009 at 3:03 PM, Wojciech Turek <[email protected]> wrote: > 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: [email protected] > Tel: (+)44 1223 763517 > > _______________________________________________ > Lustre-discuss mailing list > [email protected] > http://lists.lustre.org/mailman/listinfo/lustre-discuss > > _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
