Re: [LTP] [PATCH 2/2] fill_fs: Ensure written data is not easily compressed

Cyril Hrubis
2022-12-09T15:28:30Z

Hi!
> > The test is supposed to test what happens when filesystem is altmost
> > full and being written to, which may trigger all kinds of corner cases.
> > In that sense it makes sense to randomize the access patterns a bit so
> > that we have higher chances of utilizing different code paths. But of
> > course the question where should we stop in randomizing things and what
> > makes sense and what does not.
>
> I think there are multiple scenarious which are totally different.
>
> For example, Redis uses an append only file (AOF) and IIRC you can
> choose to batch writes for performance at the expense of data
> integrity. It's common for the AOF to have it's own volume.
>
> OTOH if we have a classic server with 1000s of daemons running, then we
> can expect writes to happen in parallel and be random.
>
> I'd be in favor of trying to test these things separately and to keep
> each scenario as simple (and reproducible) as possible. I think mixing
> together different access patterns is better handled by fuzzing.

I suppose.

Or we can run the test a few times with different access patters and do
not mix them in a single run.

--
Cyril Hrubis
chrubis@suse.cz