Hi, What is the rationale to enable or disable fadvise explicitly? do_not_use_posix_fadvise = uname(&ubuf) == 0 && strcmp(ubuf.sysname, "Linux") == 0 && strncmp(ubuf.release, "2.4", 3) <= 0; Answers as "it doesn't work" will not satisfy my hunger to this answer; because I do see a completely different performance upon manual changing this variable. Stefan