[jira] [Created] (CLOUDSTACK-7857) CitrixResourceBase wrongly calculates total memory on hosts with a lot of memory and large Dom0

["Joris van Lieshout (JIRA)" <ji...@apache.org>]

Joris van Lieshout created CLOUDSTACK-7857:
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             Summary: CitrixResourceBase wrongly calculates total memory on hosts with a lot of memory and large Dom0
                 Key: CLOUDSTACK-7857
                 URL: https://issues.apache.org/jira/browse/CLOUDSTACK-7857
             Project: CloudStack
          Issue Type: Bug
      Security Level: Public (Anyone can view this level - this is the default.)
    Affects Versions: Future, 4.3.0, 4.4.0, 4.5.0, 4.3.1, 4.4.1, 4.6.0
            Reporter: Joris van Lieshout
            Priority: Blocker


We have hosts with 256GB memory and 4GB dom0. During startup ACS calculates available memory using this formula:
CitrixResourceBase.java
	protected void fillHostInfo
		ram = (long) ((ram - dom0Ram - _xs_memory_used) * _xs_virtualization_factor);
In our situation:
	ram = 274841497600
	dom0Ram = 4269801472
	_xs_memory_used = 128 * 1024 * 1024L = 134217728
	_xs_virtualization_factor = 63.0/64.0 = 0,984375
	(274841497600 - 4269801472 - 134217728) * 0,984375 = 266211892800

This is in fact not the actual amount of memory available for instances. The difference in our situation is a little less then 1GB. On this particular hypervisor Dom0+Xen uses about 9GB.
As the comment above the definition of XsMemoryUsed allready stated it's time to review this logic. 
"//Hypervisor specific params with generic value, may need to be overridden for specific versions"

The effect of this bug is that when you put a hypervisor in maintenance it might try to move instances (usually small instances (<1GB)) to a host that in fact does not have enought free memory.
This exception is thrown:

ERROR [c.c.h.HighAvailabilityManagerImpl] (HA-Worker-3:ctx-09aca6e9 work-8981) Terminating HAWork[8981-Migration-4482-Running-Migrating]
com.cloud.utils.exception.CloudRuntimeException: Unable to migrate due to Catch Exception com.cloud.utils.exception.CloudRuntimeException: Migration failed due to com.cloud.utils.exception.CloudRuntim
eException: Unable to migrate VM(r-4482-VM) from host(6805d06c-4d5b-4438-a245-7915e93041d9) due to Task failed! Task record:                 uuid: 645b63c8-1426-b412-7b6a-13d61ee7ab2e
           nameLabel: Async.VM.pool_migrate
     nameDescription: 
   allowedOperations: []
   currentOperations: {}
             created: Thu Nov 06 13:44:14 CET 2014
            finished: Thu Nov 06 13:44:14 CET 2014
              status: failure
          residentOn: com.xensource.xenapi.Host@b42882c6
            progress: 1.0
                type: <none/>
              result: 
           errorInfo: [HOST_NOT_ENOUGH_FREE_MEMORY, 272629760, 263131136]
         otherConfig: {}
           subtaskOf: com.xensource.xenapi.Task@aaf13f6f
            subtasks: []

        at com.cloud.vm.VirtualMachineManagerImpl.migrate(VirtualMachineManagerImpl.java:1840)
        at com.cloud.vm.VirtualMachineManagerImpl.migrateAway(VirtualMachineManagerImpl.java:2214)
        at com.cloud.ha.HighAvailabilityManagerImpl.migrate(HighAvailabilityManagerImpl.java:610)
        at com.cloud.ha.HighAvailabilityManagerImpl$WorkerThread.runWithContext(HighAvailabilityManagerImpl.java:865)
        at com.cloud.ha.HighAvailabilityManagerImpl$WorkerThread.access$000(HighAvailabilityManagerImpl.java:822)
        at com.cloud.ha.HighAvailabilityManagerImpl$WorkerThread$1.run(HighAvailabilityManagerImpl.java:834)
        at org.apache.cloudstack.managed.context.impl.DefaultManagedContext$1.call(DefaultManagedContext.java:56)
        at org.apache.cloudstack.managed.context.impl.DefaultManagedContext.callWithContext(DefaultManagedContext.java:103)
        at org.apache.cloudstack.managed.context.impl.DefaultManagedContext.runWithContext(DefaultManagedContext.java:53)
        at com.cloud.ha.HighAvailabilityManagerImpl$WorkerThread.run(HighAvailabilityManagerImpl.java:831)




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