Jens, I notice that when I enable bssplit and verify, verify always fails: ... meta: verify failed at file /tmp/test offset 7143424, length 65536 open verify buf file: Read-only file system .... In my tests, the offsets that fails are always: 7143424, 15073280, 2647654, 450397184, 88080384, 88211456 it does not happen when I set a fixed size with bs, or when I do not verify. Here is the fio control file I use: [stress] filename=/tmp/test size=107374182 readwrite=randrw bssplit=64k/50:1M/50 ;bs=64k do_verify=1 verify=meta verify_interval=64k verify_dump=1 continue_on_error=verify Also, if I set a verify_interval larger than the smallest io size in bssplt, I get another kind of error. Error messages with bssplt=4k/50:1M/50: verify: bad magic header a678, wanted acca at file /tmp/test offset 9097216, length 429524186 verify: bad magic header 84b9, wanted acca at file /tmp/test offset 25268224, length 21518097 verify: bad magic header ba51, wanted acca at file /tmp/test offset 26505216, length 536429778 verify: bad magic header 1197, wanted acca at file /tmp/test offset 42139648, length 373139796 verify: bad magic header 22bf, wanted acca at file /tmp/test offset 42209280, length 493427719 meta: verify failed at file /tmp/test offset 50462720, length 65536 open verify buf file: Read-only file system open verify buf file: Read-only file system verify: bad magic header d1f6, wanted acca at file /tmp/test offset 52305920, length 322125536 verify: bad magic header 76ee, wanted acca at file /tmp/test offset 92106752, length 355054425 verify: bad magic header 821, wanted acca at file /tmp/test offset 94904320, length 460051914 I don't get these error when I set bs=4k. Are you aware of such a limitation in fio? Thanks, Gwendal. -- 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