fairly basic random write test over nfs, 1 job, directio enabled, pre-existing 1TB file results in SIGSEGV, tested on: CentOS 5.4 x86_64, 2.6.18-164.6.1.el5 kernel, fio from git, last change: Tue, 22 Dec 2009 08:06:43 +0000 fio --name=rndwrs --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=1 --size=1tb --numjobs=1 --filename=/mnt/nfs/1tb.vdb random-writers: (g=0): rw=randwrite, bs=32K-32K/32K-32K, ioengine=libaio, iodepth=4 Starting 1 process fio: pid=24153, got signal=11 Run status group 0 (all jobs): fio: file hash not empty on exit strace: [pid 23961] open("/sys/devices/system/cpu/cpu0/cache/index0/coherency_line_size", O_RDONLY) = 8 [pid 23961] read(8, "64\n", 32) = 3 [pid 23961] close(8) = 0 [pid 23961] getpriority(PRIO_PROCESS, 0) = 20 [pid 23961] setpriority(PRIO_PROCESS, 0, 0) = 0 [pid 23961] getpriority(PRIO_PROCESS, 0) = 20 [pid 23961] io_setup(4, {47657422389248}) = 0 [pid 23961] getrusage(RUSAGE_SELF, {ru_utime={0, 1999}, ru_stime={0, 0}, ...}) = 0 [pid 23961] open("/mnt/nfs/1tb.vdb", O_RDWR|O_CREAT|O_DIRECT, 0600) = 8 [pid 23961] fadvise64(8, 0, 1, POSIX_FADV_DONTNEED) = 0 [pid 23961] fadvise64(8, 0, 1, POSIX_FADV_RANDOM) = 0 [pid 23961] --- SIGSEGV (Segmentation fault) @ 0 (0) --- but no core file, since reap_threads cleans up after the sigsegv (?) with debug=all: io 26954 invalidate cache /mnt/nfs/1tb.vdb: 0/1 file 26954 goodf=1, badf=2, ff=31 file 26954 get_next_file_rr: 0x2abe73d38028 file 26954 get_next_file: 0x2abe73d38028 [/mnt/nfs/1tb.vdb] file 26954 get file /mnt/nfs/1tb.vdb, ref=1 random 26954 off rand 1425201762 random 26954 free: b=12242389915983151104, idx=536870912, bit=0 fio: pid=26954, got signal=11 process 26952 pid=26954: runstate 4 -> 9 process 26952 terminate group_id=-1 process 26952 setting terminate on random-writers/26954 diskutil 26952 update io ticks the same test works if I replace --filesize=1tb with --filesize=1gb (but makes for a far less interesting test). Regards, Case -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html