Deep Dive into SCVMM 2012 R2 Networking and Storage (Part 2)

If you would like to read the other parts in this article series please go to:

The first part of this article series explained the benefits provided by VMM host groups. As stated in the first part, VMM host groups must be created before virtualization hosts can be added under VMM management. A VMM host group serves as a management unit for configuration items such as storage, placement rules, Dynamic optimization and host reserves. In Part II, Part III and Part IV of this article series, we are going to take a look at all the configuration tabs that are available on the property page of a VMM host group and how configuring the settings help you fine tune allocation of resources to virtualization hosts located in a VMM host group. Let’s take a look at General, Placement Rules and Host Reserves Tab as part of this article.

Once Property page is opened, you have a number of configuration tabs to work with such as General, Placement rules, Host Reserves, Dynamic Optimization options, Network, Storage, and custom properties as shown in the screenshot below.

Figure 1

General Tab: On the General Tab, you can rename VMM host group, provide a description for the host group and change the location of the VMM host group. While you are given an option to change the location of the VMM host group that does not necessarily mean that you should do it without assessing the impact. Changing the location of a VMM host group would cause the child VMM host group to inherit settings from the parent VMM host group. It is recommended that before you change the location of a VMM host group, make sure VMM host group that is being moved do not inherit the settings from the parent VMM host group.

On the General tab, pay attention to “Allow unencrypted BITS file transfers” option. The overall purpose of enabling this setting is to provide security for the data that is being transferred over the network. There are a few basic things to take into considerations before enabling/disabling “Allow Unencrypted BITS file transfers” setting as listed below:

In case you have implemented another form of encryption, such as IPSec, there is no reason that you should enable encrypted file transfers setting.
For files to be transferred over an encrypted connection, the setting must be checked on both source and destination Hyper-V hosts. Similarly, the setting must be checked on both source and destination Hyper-V hosts if you need files to be transferred over an unencrypted connection.
Since allowing unencrypted file transfers improves overall performance during virtual machine live migration, it is recommended to keep this setting unchecked.

Since unencrypted settings can be enabled\disabled per VMM host group and applies to all Hyper-V hosts residing in a VMM host group, make sure to have the same setting configured for all child VMM host groups that are going to participate in the live migration events.

Placement Rules Tab: On Placement Rules tab, you can configure the placement rules for all Hyper-V hosts located in a VMM host group as shown in the screenshot below.

Figure 2

By default, a child VMM host group inherits placement rules from the parent VMM host group. In case you need to define placement rules for a child VMM host group, uncheck “Use the placement settings from the parent host group” and then define the placement rules by clicking on “Add” button as shown in the screenshot above. By default, SCVMM provides 10 custom placement rules. The placement rules help you define the conditions that VMM should consider before providing a list of virtualization hosts where the virtual machine can be deployed or migrated. The placement rules are checked when a virtual machine is live migrated to another virtualization host or when a user deploys a virtual machine via VM Templates to a virtualization host. For example, you create a custom property by name EmpType and assign the value “Permanent”. When you try to migrate or deploy a VM, virtualization host’s EmpType value that do not match the value of virtual machine, the deployment will be blocked. Similarly, when you want to deploy a new virtual machine from a VM Template, only hosts with the same value of EmpType as the VM Template will be taken into consideration.

There are four conditions provided by VMM that you can specify when configuring the placement rules as shown in the screenshot below.

Figure 3

Must Match: This indicates that the virtual machine deployment will be blocked on the destination virtualization host if virtual machine property does not match the virtualization host property. The end result is that virtual machine deployment will be blocked.
Should Match: This condition is same as “Must Match” condition except a warning message will be shown to the user about the condition mismatch.
Must Not Match: The deployment of virtual machines will be blocked if the property value matches with the destination virtualization hosts.
Should Not Match: If a condition matches, placement wizard will show a warning message to users when deploying or migrating virtual machines to destination Hyper-V hosts.

The placement rules are very helpful when you want to have granular control over the deployment of virtual machines.

Host Reserves Tab: Next tab is “Host Reserves”. As the name suggests, Host Reserves allow you to keep a pool of resources such as CPU, memory, and Disk Space reserved on all virtualization hosts residing in a VMM host group as shown in the screenshot below.

Figure 4

By default, host reserve settings are inherited from the parent VMM host group. However, you can always uncheck “Use the host reserves settings from the parent host group” option to configure host reserve settings for a child VMM host group. Host reserve settings are very useful when you have a few virtual machines that need to be up and running on a particular virtualization host. Such virtual machines do not participate in live migration events and are always up and running on a particular virtualization host. Before the virtual machines can be placed on a virtualization host, the host must be able to meet the resource requirements of virtual machines without considering the host reserves. VMM always takes host reserve settings of virtualization hosts into consideration before the virtual machine can be moved to a virtualization host.

Note:
Host reserves setting can be configured for individual VMM host groups and for individual virtualization hosts. As part of the host reserve setting, you can configure CPU, Memory, Disk Space, Disk I/O and Network I/O as shown in the screenshot above.

Summary

In this article, we explained configuration tabs that are available on the property page of a VMM host group. We explained the use of Placement Rules that VMM uses before a virtual machine can be placed on a virtualization host. We also explained host reserve settings that are used to reserve a pool of resources on the virtualization hosts residing in a VMM host group.

In the third part of this article series, we will continue to look at the other configuration tabs such as dynamic optimization options, storage, networking, and custom properties.

If you would like to read the other parts in this article series please go to: