On 02/08/2018 07:23 AM, Edgar Kaziakhmedov wrote:
Upstream NBD protocol implementation supports an efficient zero out
mechanism over the wire, along with the ability to check whether a
client allows using a hole.
Accordingly, since PWRITE_ZERO doesn't involve any payload on the wire,
increase a maximum size of the PWRITE_ZERO request up to 1Gb (aligned).
Moreover, such change will decrease the number of PWRITE_ZERO NBD commands
in comparison with the current 32M limit. The benefits of
the larger constraint can be examined in a block mirroring over NBD.
Signed-off-by: Edgar Kaziakhmedov <edgar.kaziakhme...@virtuozzo.com>
---
block/nbd.c | 2 +-
include/block/nbd.h | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)
I've posted a counter-proposal series that should accomplish the same
effect, but in a way (soon to be) sanctioned by the NBD spec:
https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg00135.html
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
