On 01/08/2025 07:41, Ojaswin Mujoo wrote:
Got it, I think I can make this test work for ext4 only but then it might
be more appropriate to run the fio tests directly on atomic blkdev and
skip the FS, since we anyways want to focus on the storage stack.
testing on ext4 will prove also that the FS and iomap behave correctly
in that they generate a single bio per atomic write (as well as testing
the block stack and below).
I'll try to check if we can modify the tests to write on non-overlapping
ranges in a file.
JFYI, for testing SW-based atomic writes on XFS, I do something like this. I
have multiple threads each writing to separate regions of a file or writing
to separate files. I use this for power-fail testing with my RPI. Indeed, I
have also being using this sort of test in qemu for shutting down the VM
when fio is running - I would like to automate this, but I am not sure how
yet.
Please let me know if you want further info on the fio script.
Got it, thanks for the insights. I was thinking of something similar now
where I can modify the fio files of this test to write on non
overlapping ranges in the same file. The only doubt i have right now is
that when I have eg, numjobs=10 filesize=1G, how do i ensure each job
writes to its own separate range and not overlap with each other.
I saw the offset_increment= fio options which might help, yet to try it
out though. If you know any better way please do share.
Yeah, so I use something like:
--numjobs=2 --offset_align=0 --offset_increment=1M --size=1M
Thanks,
John
