I have done parallel KVM migrations without issue, it's "supposed to work". Really I think it's in the same boat as parallel start/stop. It should work, but the config option is there just in case. I think we should add it.
On Thu, Oct 3, 2013 at 11:41 AM, Chip Childers <chip.child...@sungard.com> wrote: > On Thu, Oct 03, 2013 at 11:44:46AM -0500, Alex Ough wrote: >> I'm not sure what else commands 'MigrateCommand' actually execute in >> addition to 'Start/Stop/CopyCommand', but can we include 'MigrateCommand' >> if it consists of only those 3 commands? >> >> Thanks >> Alex Ough > > In the case of VMware, the migrate command is executed via the > MigrateVMTask that's part of the VMware SDK (see > vmware-base/src/com/cloud/hypervisor/vmware/mo/VirtualMachineMO.java). > > For VMware, I know that vCenter will queue and process concurrent > requests for migrations. Specifically, it will throttle the migrations > happening, based on it's internal concurrency constraints, but the task > queue will still accept more connections. Obviously the risk are the > VMware layer tasks timing out if it takes too long for the task queue to > complete. > > As for XenServer, it's happening in what appears to be a similar way > (although the source host is the target for the migration API call). > > Check > plugins/hypervisors/xen/src/com/cloud/hypervisor/xen/resource/CitrixResourceBase.java. > > I'm not familiar enough with XenServer's concurrency model for > migrations. Any experts know the answer to if it can handle concurrency > in a stable way? > > With KVM, it's obviously executing via the agent. Similarly to > XenServer, I'm not familiar enough to know about concurrent operations. > > So do the HV experts on the list have any opinions about XenServer and > KVM migration concurrency? > > -chip > >
