Description of problem:
Many VDSErrorException occurs during mass VMs migration which are running on fake hosts. 

Version-Release number of selected component (if applicable):
RHEVM 3.4.0-0.16.rc.el6ev
OS Version: RHEL - 6Server - 6.5.0.1.el6
Kernel Version: 2.6.32 - 431.5.1.el6.x86_64
KVM Version: 0.12.1.2 - 2.415.el6_5.6
LIBVIRT Version: libvirt-0.10.2-29.el6_5.5
VDSM Version: vdsm-4.14.7-0.2.rc.el6ev

How reproducible:
Environment: 2 Data Center (Real and Fake),
2 NFS Storage Domains (Real and Fake),
4 real hosts (24 CPU, 64 G),
200 real VMs,
200 fake hosts,
1500 fake VMs.
Perform JMeter script with 100 threads for migrate fake VMS
VDSErrorException occurs during mass VMs migration.

Steps to Reproduce:
1.
2.
3.

Actual results:
1.
2014-05-14 07:48:26,966 ERROR [org.ovirt.engine.core.vdsbroker.vdsbroker.MigrateStatusVDSCommand] (org.ovirt.thread.pool-4-thread-11) [390924d3] Failed in MigrateStatusVDS method
2014-05-14 07:48:26,967 INFO [org.ovirt.engine.core.vdsbroker.vdsbroker.MigrateStatusVDSCommand] (org.ovirt.thread.pool-4-thread-11) [390924d3] Command org.ovirt.engine.core.vdsbroker.vdsbro
ker.MigrateStatusVDSCommand return value
 StatusOnlyReturnForXmlRpc [mStatus=StatusForXmlRpc [mCode=12, mMessage=Fatal error during migration]]
2014-05-14 07:48:26,967 INFO [org.ovirt.engine.core.vdsbroker.vdsbroker.MigrateStatusVDSCommand] (org.ovirt.thread.pool-4-thread-11) [390924d3] HostName = fake_host_69
2014-05-14 07:48:26,967 ERROR [org.ovirt.engine.core.vdsbroker.vdsbroker.MigrateStatusVDSCommand] (org.ovirt.thread.pool-4-thread-11) [390924d3] Command MigrateStatusVDSCommand(HostName = fake_host_69, HostId = c2d01b2e-e1bd-4233-af26-379a186a7e71, vmId=098bdb18-cc21-4e7a-9838-df512a5609a6) execution failed. Exception: VDSErrorException: VDSGenericException: VDSErrorException: Failed to MigrateStatusVDS, error = Fatal error during migration, code = 12
2014-05-14 07:48:26,967 INFO [org.ovirt.engine.core.vdsbroker.vdsbroker.MigrateStatusVDSCommand] (org.ovirt.thread.pool-4-thread-11) [390924d3] FINISH, MigrateStatusVDSCommand, log id: 7811c0df
2014-05-14 07:48:26,972 INFO [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (org.ovirt.thread.pool-4-thread-11) [390924d3] Correlation ID: 7bbf5060, Job ID: 874a688b-9f0e-409f-bb1c-c0794745596e, Call Stack: null, Custom Event ID: -1, Message: Migration failed due to Error: Fatal error during migration. Trying to migrate to another Host (VM: fake_490, Source: fake_host_69, Destination: fake_host_105).

2.
2014-05-14 08:02:05,865 INFO [org.ovirt.engine.core.vdsbroker.vdsbroker.DestroyVDSCommand] (DefaultQuartzScheduler_Worker-28) [34065ecb] START, DestroyVDSCommand(HostName = fake_host_32, HostId = 78b0e5a2-08df-43f5-8004-67285ce4a2c2, vmId=209701d0-6e97-4cf6-ab92-ba4dfe410686, force=false, secondsToWait=0, gracefully=false), log id: 316fcb34
2014-05-14 08:02:05,866 WARN [org.ovirt.engine.core.utils.threadpool.ThreadPoolUtil] (org.ovirt.thread.pool-4-thread-13) Executing a command: java.util.concurrent.FutureTask , but note that there are 16 tasks in the queue.
2014-05-14 08:02:05,873 WARN [org.ovirt.engine.core.vdsbroker.VdsManager] (DefaultQuartzScheduler_Worker-94) [1d49a2f0] Failed to refresh VDS , vds = 03d530a7-fb23-4131-a85d-54346028ce4b : fake_host_3, error = org.ovirt.engine.core.vdsbroker.vdsbroker.VDSErrorException: VDSGenericException: VDSErrorException: Failed to GetAllVmStatsVDS, error = Unexpected exception, code = 16, continuing.: org.ovirt.engine.core.vdsbroker.vdsbroker.VDSErrorException: VDSGenericException: VDSErrorException: Failed to GetAllVmStatsVDS, error = Unexpected exception, code = 16
        at org.ovirt.engine.core.vdsbroker.vdsbroker.VdsBrokerCommand.createDefaultConcreteException(VdsBrokerCommand.java:61) [vdsbroker.jar:]
        at org.ovirt.engine.core.vdsbroker.vdsbroker.BrokerCommandBase.createException(BrokerCommandBase.java:199) [vdsbroker.jar:]
        at org.ovirt.engine.core.vdsbroker.vdsbroker.BrokerCommandBase.proceedProxyReturnValue(BrokerCommandBase.java:186) [vdsbroker.jar:]
        at org.ovirt.engine.core.vdsbroker.vdsbroker.GetAllVmStatsVDSCommand.executeVdsBrokerCommand(GetAllVmStatsVDSCommand.java:21) [vdsbroker.jar:]
        at org.ovirt.engine.core.vdsbroker.vdsbroker.VdsBrokerCommand.executeVDSCommand(VdsBrokerCommand.java:96) [vdsbroker.jar:]
        at org.ovirt.engine.core.vdsbroker.VDSCommandBase.executeCommand(VDSCommandBase.java:56) [vdsbroker.jar:]
        at org.ovirt.engine.core.dal.VdcCommandBase.execute(VdcCommandBase.java:31) [dal.jar:]
        at org.ovirt.engine.core.vdsbroker.ResourceManager.runVdsCommand(ResourceManager.java:413) [vdsbroker.jar:]
        at org.ovirt.engine.core.vdsbroker.VdsUpdateRunTimeInfo.fetchRunningVms(VdsUpdateRunTimeInfo.java:954) [vdsbroker.jar:]
        at org.ovirt.engine.core.vdsbroker.VdsUpdateRunTimeInfo.refreshVmStats(VdsUpdateRunTimeInfo.java:910) [vdsbroker.jar:]
        at org.ovirt.engine.core.vdsbroker.VdsUpdateRunTimeInfo.refreshVdsRunTimeInfo(VdsUpdateRunTimeInfo.java:507) [vdsbroker.jar:]
        at org.ovirt.engine.core.vdsbroker.VdsUpdateRunTimeInfo.refresh(VdsUpdateRunTimeInfo.java:344) [vdsbroker.jar:]
        at org.ovirt.engine.core.vdsbroker.VdsManager.onTimer(VdsManager.java:231) [vdsbroker.jar:]
        at sun.reflect.GeneratedMethodAccessor10.invoke(Unknown Source) [:1.7.0_55]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.7.0_55]
        at java.lang.reflect.Method.invoke(Method.java:606) [rt.jar:1.7.0_55]
        at org.ovirt.engine.core.utils.timer.JobWrapper.execute(JobWrapper.java:60) [scheduler.jar:]
        at org.quartz.core.JobRunShell.run(JobRunShell.java:213) [quartz.jar:]
        at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:557) [quartz.jar:] 

Expected results:
no exception

Additional info: