On 1/13/21 8:06 AM, Max Reitz 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 the job is being drained. > > 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 <mre...@redhat.com> > --- > tests/qemu-iotests/129 | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Eric Blake <ebl...@redhat.com> > > diff --git a/tests/qemu-iotests/129 b/tests/qemu-iotests/129 > index e6753c90ef..c3ad584ba2 100755 > --- a/tests/qemu-iotests/129 > +++ b/tests/qemu-iotests/129 > @@ -69,7 +69,7 @@ class TestStopWithBlockJob(iotests.QMPTestCase): > def test_drive_mirror(self): > self.do_test_stop("drive-mirror", device="drive0", > target=self.target_img, format=iotests.imgfmt, > - sync="full") > + sync="full", buf_size=65536) > > def test_drive_backup(self): > self.do_test_stop("drive-backup", device="drive0", > -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org