* Denis V. Lunev (address@hidden) wrote:
On 08/02/2018 12:50 PM, Dr. David Alan Gilbert wrote:
* Denis V. Lunev (address@hidden) wrote:
I don't quite understand the last two paragraphs.
we are thinking right now to eliminate delay on regular IO
for migration. There is some thoughts and internal work in
progress. That is why I am worrying.
What downtime are you typicaly seeing and what are you aiming for?
It would be good if you could explain what you're planning to
fix there so we can get a feel for it nearer the start of it
rather than at the end of the reviewing!
Dave
The ultimate goal is to reliable reach 100 ms with ongoing IO and
you are perfectly correct about reviewing :)
That would be neat.
Though the problem is that right now we are just trying to
invent something suitable :(
OK, some brain-storm level ideas:
a) Throttle the write bandwidth at later stages of migration
(I think that's been suggested before)
b) Switch to some active-sync like behaviour where the writes
are sent over the network as they happen to the destination
(mreitz has some prototype code for that type of behaviour
for postcopy)
c) Write the writes into a buffer that gets migrated over the
migration stream to get committed on the destination side.
As I say, brainstorm level ideas only!
Dave