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Date: Fri, 18 Jul 2014 09:47:48 +0200
From: Jens Axboe <axboe@kernel.dk>
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Subject: Re: [fio-2.1.9] verify and bssplit do not work together
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To: Gwendal Grignou <gwendal@chromium.org>, Puthikorn Voravootivat <puthik@chromium.org>, fio@vger.kernel.org
List-ID: <fio@vger.kernel.org>

On 2014-07-17 22:36, Gwendal Grignou wrote:
> 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

That does sound like a bug. Out of curiosity, does anything change if 
you set experimental_verify=1 in the job?

I'll take a look at this next week, currently away on vacation.

> 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?

Fio doesn't support verify intervals larger than a single written block, 
so that is something the parser or option checker should catch. 
Apparently it doesn't. I'll take a look at this too.


-- 
Jens Axboe