> ^^^ Here's a problem - you can't randomly write and then verify sequentially via a different run. In your case you need rw=randread. Yes. It's my fault to paste the original content of the buggy job file. I understand that rw= option should be paired with or without rand- prefix. > The randseed is the same across different invocations of fio unless you say otherwise (see randrepeat - http://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-randrepeat > ). So even if you weren't using a verification state file you will re-generate the same pattern if the rest of the job is the same. Thank you for the explanation. A deep question about the seed comes:) Though randseed is the same across different invocation of fio, is it different for different sections in one job file? I made another job file as below: myjob.fio: [global] bs=4k direct=1 ioengine=sync verify=crc32c filename=/dev/sdf io_size=10k [write-phase] rw=randwrite do_verify=0 write_iolog=iolog [verify-phase] stonewall rw=randread do_verify=1 I think these two sections have the same settings except the date direction. So I expect the later one can verify the write-phase. But it failed. run it with --debug, and found the offset generated are not the same, so verify abort with error for the first time, as below: random 24382 off rand 259043585 io 24382 fill_io_u: io_u 0x25ad740: off=71233536/len=4096/ddir=1//dev/sdf random 24382 off rand 3179521932 io 24382 fill_io_u: io_u 0x25ad740: off=874364928/len=4096/ddir=1//dev/sdf random 24382 off rand 3621444214 io 24382 fill_io_u: io_u 0x25ad740: off=995893248/len=4096/ddir=1//dev/sdf random 24388 off rand 1094293889 io 24388 fill_io_u: io_u 0x25ad500: off=300929024/len=4096/ddir=0//dev/sdf You can see [24382] is write-phase and [24388] is verify-phase, and the first round of them use different seed I suppose. I search in the source code, and found the following snippet: static int setup_random_seeds(struct thread_data *td) { ... for (i = 0; i < FIO_RAND_NR_OFFS; i++) { td->rand_seeds[i] = seed * td->thread_number + i; seed *= 0x9e370001UL; } Is td->thread_number different for different sections? I thought they both equal to 1 before. Later, I realize split verify using two sections in one file is not a formal way? Is it better to just write only one write section, and use 'fio --verify-only jobfile' to do the split verification as the updated one below? myjob.fio updated: [global] bs=4k direct=1 ioengine=sync verify=crc32c filename=/dev/sdf io_size=10k [write-phase] rw=randwrite do_verify=0 Thank you very much again! Regards, Vaughan -- 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
