[Users] SPM and VM migrations

[Doron Fediuck]

----- Original Message -----
| From: "Christian Kolquist" <ckolquist at rgmadvisors.com>
| To: users at ovirt.org
| Sent: Tuesday, July 2, 2013 11:01:55 PM
| Subject: [Users] SPM and VM migrations
| 
| I currently have an issue where when we migrate more than one VM from the
| host that is the SPM to another host it will cause connectivity to the SPM
| Host to fail which the ovirt engine then sees the host being down. It then
| reboots the SPM Host and stops all of the VM's running on there.
| 
| 
| Our setup
| 
| Nodes: Fedora 18
| em1: ovirtmgmt (mgmt, storage and migrations)
| em2: VM network trunks
| 
| Engine: Fedora 17 (will be upgrading that to fedora 18 shortly)
| 
| Both NICS are 1 GB. The storage is NFS which is on the same VLAN and subnet
| as the hosts. The ovirt-engine is on a standalone server but is NOT on the
| same vlan/subnet yet.
| 
| Is this normal behavior for the SPM to have issue when migrating hosts to and
| from it? I don't have any further network interfaces to add to the hosts at
| this time (we are planning on adding a 2x 10GB card to each node in the
| future but we don't have that option at this time). Is there anyway to limit
| the number of active migrations and have the migrations be a lower priority
| traffic than others?
| 
| 
| Thanks
| Christian
| 
| 
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| 

Hi Christian,
Apparently the migration is eating up your bandwidth.
Currently it is possible to hard-limit the migration using
The /usr/share/doc/<vdsm-version>/vdsm.conf.sample file with

# Maximum bandwidth for migration, in mbps, 0 means libvirt's default (30mbps?).
# migration_max_bandwidth = 0

In the coming oVirt 3.3 we should be able to handle this by separating
the migration network, and then use-
http://www.ovirt.org/Features/Network_QoS

Doron