On Sat, Nov 30, 2013 at 12:25:31AM +0200, Itamar Heim wrote:
On 11/29/2013 02:08 PM, Dan Kenigsberg wrote:
On Fri, Nov 29, 2013 at 11:49:05AM +0100, Ernest Beinrohr wrote:
I want to put some of my hvs to maintenance, but that causes a migration storm, which causes an temporary unavailability of the hv and ovirt fences it, while migrations are still running.
So I have to migrate one-by-one manually and then put the hv to maintenance.
Is it possible to limit migration speed and number of concurrent migrations?
You could set max_outgoing_migrations to 1 (in each /etc/vdsm/vdsm.conf), but even a single VM migrating may choke your connection (depends which wins, the CPU running qemu, or your bandwidth).
Currently, your only option is to define a migration network for your cluster (say, over a different nic, or over a vlan), and use tools external to ovirt to throtle the bandwidth on it (virsh net-edit <network name> and http://libvirt.org/formatnetwork.html#elementQoS can come up handy). ovirt-3.4 should expose the ability to set QoS limits on migration networks.
I thought we can control both the number of concurrent migrations and the bandwidth per migration which defaults to 30MB/s?
You are perfectly right: I forgot about 'migration_max_bandwidth', which vdsm sets to 32MiBps (per single migration). Sorry for misleading the list and its archives.