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https://issues.apache.org/jira/browse/CLOUDSTACK-7857?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14216355#comment-14216355
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Joris van Lieshout commented on CLOUDSTACK-7857:
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I'm not too familiar with mem overhead on other hypervisors. You would think
the formula would be some what the same. I understand that ACS has to be as
flexible as possible but what if the logic of calculating free mem is moved to
the hypervisor plugin so the logic in calculating can be specific but the
outcome used by generic processes the same? I'm not a developer so my apologies
if my comment does not make any sense.
In the end any hypervisor should be able to provide some information about
available memory, either by calculation of with a direct metric. Perhaps this
will always be something hypervisor specifies...?
> 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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