Re: [PATCH v3 08/10] iotests/129: Limit mirror job's buffer size

[Willian Rampazzo]

On Thu, Jan 14, 2021 at 2:37 PM Max Reitz <mreitz@redhat.com> wrote:
>
> Issuing 'stop' on the VM drains all nodes.  If the mirror job has many
> large requests in flight, this may lead to significant I/O that looks a
> bit like 'stop' would make the job try to complete (which is what 129
> should verify not to happen).
>
> We can limit the I/O in flight by limiting the buffer size, so mirror
> will make very little progress during the 'stop' drain.
>
> (We do not need to do anything about commit, which has a buffer size of
> 512 kB by default; or backup, which goes cluster by cluster.  Once we
> have asynchronous requests for backup, that will change, but then we can
> fine-tune the backup job to only perform a single request on a very
> small chunk, too.)
>
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  tests/qemu-iotests/129 | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>

Reviewed-by: Willian Rampazzo <willianr@redhat.com>