Il 04/02/2014 12:59, Alexey Kardashevskiy ha scritto:
> With the default throttling of 32 MiB/s, bandwidth must be something like
> 33000 (expressed in bytes/ms) with the default settings, and then max_size
> should be 33000*3*10^9 / 10^6 = 6000000. Where is my computation wrong?
migrate_max_downtime() = 30000000 = 3*10^7.
Oops, that's the mistake.
When the migration is in iterating stage, bandwidth is a speed in last
100ms which is usually 5 blocks 250KB each so it is
1250000/100=12500bytes/s and max_size=12500*30000000/10^6=375000 which is
less than the last chunk is.
Perhaps our default maximum downtime is too low. 30 ms doesn't seem
achievable in practice with 32 MiB/s bandwidth. Just making it 300 ms
or so should fix your problem.
Paolo
