Re: replay blktrace to different device

Re: replay blktrace to different device

[Alireza Haghdoost]

Dear Sebastian

Did you find any way to reply trace on another device ?


Alireza Haghdoost


>> I'm running fio like this:
>> # fio --name=replay --filename=/dev/sdc --read_iolog=trace_input_fio
>> and it aborts with
>> fio: filesetup.c:855: get_file: Assertion `fio_file_open(f)' failed.
>I captured another trace, this time for /dev/sdc, tried again using it
>as input to read_iolog
>and got the same error message.
>So it looks like there is a general problem with "read_iolog" in fio 1.38?
>I can supply the "--debug=all" logfile if needed.
>Thanks!
>- Sebastian
--

Re: replay blktrace to different device

[Jens Axboe]

On 2010-11-20 08:34, Alireza Haghdoost wrote:
> Dear Sebastian
> 
> Did you find any way to reply trace on another device ?

You can do that with the replay_redirect option. See the man page or the
HOWTO. You need a fairly recent fio to do that.

-- 
Jens Axboe

replay blktrace to different device

[Sebastian Färber]

Hi,

i discovered that fio is able to replay captured blktrace patterns and
just tried it ... without luck.
It seems that fio can only replay the blktrace to the device that the
trace was captured on?

I did a blktrace on one of my servers which uses /dev/md1 as its main
device and tried replaying
the patterns on another server where i prepared a spare device (/dev/sdc).

I'm running fio like this:
# fio --name=replay --filename=/dev/sdc --read_iolog=trace_input_fio
and it aborts with
fio: filesetup.c:855: get_file: Assertion `fio_file_open(f)' failed.

I also enabled --debug=all and noticed that while parsing the blktrace
fio adds /dev/md1 to it's list of devices.
The system i'm running fio on also has a /dev/md1 but this is my
root-device and i don't want fio to run the r/w benchmark
there.
Is this a bug or would it be possible to modify fio so "--filename"
overrides the device in captured trace?

- Sebastian

Re: replay blktrace to different device

[Sebastian Färber]

> I'm running fio like this:
> # fio --name=replay --filename=/dev/sdc --read_iolog=trace_input_fio
> and it aborts with
> fio: filesetup.c:855: get_file: Assertion `fio_file_open(f)' failed.

I captured another trace, this time for /dev/sdc, tried again using it
as input to read_iolog
and got the same error message.
So it looks like there is a general problem with "read_iolog" in fio 1.38?
I can supply the "--debug=all" logfile if needed.

Thanks!

- Sebastian

Re: replay blktrace to different device

[Jens Axboe]

On Sun, May 16 2010, Sebastian F�rber wrote:
> > I'm running fio like this:
> > # fio --name=replay --filename=/dev/sdc --read_iolog=trace_input_fio
> > and it aborts with
> > fio: filesetup.c:855: get_file: Assertion `fio_file_open(f)' failed.
> 
> I captured another trace, this time for /dev/sdc, tried again using it
> as input to read_iolog
> and got the same error message.
> So it looks like there is a general problem with "read_iolog" in fio 1.38?
> I can supply the "--debug=all" logfile if needed.

I'll take a look.

-- 
Jens Axboe