RHEL Kernel Performance Optimization, Characterization ... - Red Hat

RHEL3 /proc/sys/vm/bdflushint nfract; /* Percentage of buffer cache dirty to activate bdflush */int ndirty; /* Maximum number of dirty blocks to write out per wake­cycle */int dummy2; /* old "nrefill" */int dummy3; /* unused */int interval; /* jiffies delay between kupdate flushes */int age_buffer; /* Time for normal buffer to age before we flush it */int nfract_sync;/* Percentage of buffer cache dirty to activate bdflush synchronouslyint nfract_stop_bdflush; /* Percetange of buffer cache dirty to stop bdflush */int dummy5; /* unused */Example:Settings for Server with ample IO config (default r3 geared for ws)sysctl ­w vm.bdflush=”50 5000 0 0 200 5000 3000 60 20 0”