// // Some read activity through the buffer cache and the cache read // hit ratio is less than 80% // (lots of file system reads causing physical I/O) // delta = 1 min; // check every minute blkio = "kernel.all.io"; poor_read_hits = (($blkio.lread - $blkio.bread) / $blkio.lread) < 0.8 && $blkio.lread > 100 -> alarm 20 min "poor buffer cache read hit ratio (%v)"; // Note: %v in alarm string is bound to the left most // expression in the predicate