[CentOS-virt] 6.5 live migration speed

Sat Dec 28 10:01:53 UTC 2013
Ulrich Leodolter <ulrich.leodolter at obvsg.at>

hello,

while upgrading a kvm virtualization cluster from c6.4 to c6.5
and i am no longer able to control the migration speed.

in c6.4 the default speed was the maximum bandwidth (1g in my case)
and the actual migration speed was about 100MB/s.

now in c6.5 the actual migration speed dropped down to about
25MB/s - 50MB/s,  it varies and sometimes during migration of
huge machines (36GB) i was at 100MB/s, but only for seconds.

i tried also to set speed using this command:

virsh migrate-setspeed <domain> --bandwidth 1000

but it seems it has no affect,  i remember in c6.3 the default
migration speed was 33% of total bandwidth and at that time
the above command worked and 100% were used during migration.

can anyone confirm this ??

thanks
ulrich