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Bug 1404762

Summary:	[Docs][Admin] Fix description of HighVmCount scheduling parameter
Product:	Red Hat Enterprise Virtualization Manager	Reporter:	Martin Sivák <msivak>
Component:	Documentation	Assignee:	Megan Lewis <melewis>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Byron Gravenorst <bgraveno>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	4.0.5	CC:	lbopf, lsurette, msivak, rbalakri, Rhev-m-bugs, srevivo, ykaul, ylavi
Target Milestone:	ovirt-4.1.3
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
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Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
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Last Closed:	2017-08-04 03:55:37 UTC	Type:	Bug
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Documentation:	---	CRM:
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oVirt Team:	Docs	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1404247
Bug Blocks:

Description Martin Sivák 2016-12-14 15:10:02 UTC

The docs currently say this in table 5.7 [1].

HighVmCount: Sets the maximum number of virtual machines that can run on each host. Exceeding this limit qualifies the host as overloaded. The default value is 10.


But that is wrong. We do not consider a cluster with 10 VMs overloaded. The number just describes a count limit under which there will be no balancing. There is not much sense in moving VMs around when your hosts are almost empty.


[1] https://access.redhat.com/documentation/en/red-hat-virtualization/4.0/single/administration-guide/

Comment 1 Lucy Bopf 2017-04-27 06:53:42 UTC

Assigning to Megan for review.

Megan, this bug is closely related to your recent work on scheduling policies, so should be a quick one to tackle.

Comment 4 Martin Sivák 2017-06-02 14:14:06 UTC

It is still wrong. "Sets the maximum number of virtual machines that can run on each host." this is not true.

The meaning of highVmCount is: Sets the minimal number of virtual machines that have to be running in a cluster to enable load balancing. The default value is 10 running VMs.

In other words - there will be no load balancing when there are less VMs running than defined by highVmCount.

Comment 5 Martin Sivák 2017-06-02 14:17:23 UTC

Oh it is actually even more strict. The value is not per cluster, but per host. So the meaning is - balancing is only enabled when there is at least one host with at least highVmCount running VMs.

Comment 17 Megan Lewis 2017-08-04 03:55:37 UTC

The changes for this bug have now been published: 
4.1: 
https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.1/html-single/administration_guide/#sect-Explanation_of_Settings_and_Controls_in_the_New_Cluster_and_Edit_Cluster_Windows 

https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.1/html-single/administration_guide/#Configuring_scheduling_policy

4.0: 
https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.0/html-single/administration_guide/#sect-Explanation_of_Settings_and_Controls_in_the_New_Cluster_and_Edit_Cluster_Windows

https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.0/html-single/administration_guide/#Configuring_scheduling_policy