On 02/10/2016 08:57 AM, Denis V. Lunev wrote: > On 02/10/2016 01:08 PM, Stefan Hajnoczi wrote: >> On Sat, Jan 30, 2016 at 01:56:30PM +0300, Vladimir Sementsov-Ogievskiy >> wrote: >>> Add qmp command to query dirty bitmap contents. This is needed for >>> external backup. >>> >>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> >>> --- >>> block/dirty-bitmap.c | 55 >>> +++++++++++++++++++++++++++++++++++++++ >>> blockdev.c | 62 >>> ++++++++++++++++++++++++++++++++++++++++++++ >>> include/block/dirty-bitmap.h | 7 +++++ >>> qapi/block-core.json | 54 >>> ++++++++++++++++++++++++++++++++++++++ >>> qmp-commands.hx | 33 +++++++++++++++++++++++ >>> 5 files changed, 211 insertions(+) >> This API produces large replies and/or requires many calls to fetch all >> bitmap data. The worst case is a 101010... bitmap. >> >> I consider the dirty bitmap to be data (vs control) and not something >> that should be sent over a control channel like the QMP monitor. >> >> How about writing the dirty bitmap to a file? The new bitmap file >> format that Fam is working on could be used. That way the dirty bitmap >> can be saved asynchronously without hogging the QMP monitor. > Reasonable point. > > May be it would be better to setup "special" NBD server inside > QEMU which will allow to directly "read" bitmap data. > > Any opinion? > > Den
Or perhaps something like migration, where the client receiving the data opens a socket of some sort, and QEMU connects to that socket to send the data.
