Single iolog file created when 2 separate files are expected (write_iolog)

Single iolog file created when 2 separate files are expected (write_iolog)

[freoone]

Hi,

I'm trying to run fio to do some random reads with 2 threads
(numjobs=2). I'd like to record iolog for both threads in separate
files.
The manual in the 'write_iolog' section says:
"Specify a separate file for each job, otherwise the iologs will be
interspersed and the file may be corrupt."
and later:
"You can specify a number of files by separating the names with a ‘:’
character."
So I'm running the following command:
./fio  --name=test2jobs --rw=randread --filename=file.fio --size=10M
--numjobs=2 --write_iolog=log1:log2
but instead of two files "log1" and "log2" I get a single file
"log1:log2" containing IOs from both threads.
Is this a bug in fio or is there some misconception on my part?

I'm running Arch Linux 5.13.13-arch1-1, fio-3.28-18-gf3057

Thank you in advance.

Re: Single iolog file created when 2 separate files are expected (write_iolog)

[Sitsofe Wheeler]

Hi,

On Tue, 21 Sept 2021 at 09:30, freoone <freoone@gmail.com> wrote:
>
>
> I'm trying to run fio to do some random reads with 2 threads
> (numjobs=2). I'd like to record iolog for both threads in separate
> files.
> The manual in the 'write_iolog' section says:
> "Specify a separate file for each job, otherwise the iologs will be
> interspersed and the file may be corrupt."
> and later:
> "You can specify a number of files by separating the names with a ‘:’
> character."

The text "you can specify a number of files by separating the names
with a ‘:’ colon" only applies to the explicit filename option
(https://fio.readthedocs.io/en/latest/fio_man.html#cmdoption-arg-filename
) as opposed to other options (like write_iolog) that happen be
filenames.

> So I'm running the following command:
> ./fio  --name=test2jobs --rw=randread --filename=file.fio --size=10M
> --numjobs=2 --write_iolog=log1:log2
> but instead of two files "log1" and "log2" I get a single file
> "log1:log2" containing IOs from both threads.
> Is this a bug in fio or is there some misconception on my part?

To get what you describe you have to avoid usage of numjobs. For
example if I leave make most of the options as global then this works:
./fio --rw=randread --filename=file.fio --size=10M  --name=testjob1
--write_iolog=log1  --name=testjob2 --write_iolog=log2

-- 
Sitsofe