Thank you for you email, Yes readahead is enabled and it set to it's default value. Settings are exactly the same on RHEL4 and RHEL5 nodes.
Cheers W 2009/11/15 Mag Gam <[email protected]> > 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 > > > > > -- -- Wojciech Turek Assistant System Manager High Performance Computing Service University of Cambridge Email: [email protected] Tel: (+)44 1223 763517
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