DRS Flashcards
The hosts in the cluster must be part of a vSphere vMotion migration network to use vSphere DRS for _______ __________,
load balancing
To use shared storage, configure all hosts in the cluster: Datastores must be accessible by _____ and ______ hosts.
source
destination
For DRS to work you must place the disks of all virtual machines on ____ ______ that is accessible by source and destination hosts.
shared storage
To use vSphere DRS for load balancing, the hosts in your cluster must be part of a vSphere _______ _______.
vMotion network
For the initial placement of virtual machines and dynamic balancing while virtual machines are running, you need to configure the _____ ______
automation level
What are the three different automation levels?
Manual
Partially automated
Fully Automated
Which automation level does the following: When you power on a vm, vSphere DRS displays a list of recommended hosts on which to place the vm. When the cluster becomes imbalanced, vSphere DRS displays recommendations for vm migration.
Manual
Which automation level does the following: When you power on a vm, vSphere DRS places it on the best-suited host. When the cluster becomes imbalanced, vSphere DRS displays recommendations for manual vm migration.
Partially automated
Which automation level does the following: When you power on a vm, vSphere DRS places it on the best-suited host. When the cluster becomes imbalanced, vSphere DRS migrates virtual machines from overutilized hosts to underutilized hosts to ensure a balanced use of cluster resources.
Fully automated
What determines how aggressively vSphere DRS selects to migrate virtual machines?
migration threshold
What does the migration threshold do?
• determines how aggressively vSphere DRS selects to migrate vms
When Predictive DRS is enabled, The vSphere DRS data collector retrieves statistics from what 2 sources?
• Resource usage statistic from hosts
• Predictive statistic from VMware vRealize® Operations™ server
The predicted usage statistics always take precedence over current usage statistics.
By utilizing statistics from vRealize Operations, vSphere DRS can analyze ______ workload on virtual machines in the near future.
expected
vSphere DRS can use the _____ _______ values with the current usage values to make placement decisions in advance of the resources being requested.
predicted workload
What are affinity rules?
• Use for multi virtual machine systems where virtual
machines communicate heavily with one another.
ex: performance reasons
What are anti affinity rules?
• Use for multi virtual machine systems where load balance or high availability is desired.
ex. availability reasons
VM or host groups are used in defining _______ _______
affinity rules.
You can create one or more vm or host groups in a vSphere DRS cluster, each consisting of one or more vm’s. A vm and host can belong to _____ ______
multiple groups
A Virtual Machines to Hosts affinity rule includes the following components: (3)
• A virtual machine DRS group • A host DRS group • A designation of whether the rule is a: -- requirement (must) --preference (should) --affinity (run on) --or anti-affinity (not run on).
A _________ rule is softly enforced and can be violated if necessary
preferential
Ex: Separate virtual machines on different blade systems.
A _______ rule is strictly enforced and can never be violated.
required
Ex: Enforce host-based ISV licensing.
The vSphere DRS tab displays information about the vSphere DRS recommendations made for the cluster, the_____ that occurred in applying such recommendations, and the _____of vSphere DRS
actions.
faults, history
Reasons why vSphere HA might not be able to fail over virtual machines:
• vSphere HA admission control is disabled, and resources are insufficient in the remaining hosts to power on all of the failed VMs.
• Required VM-Host affinity rules prevent vSphere HA from failing over.
• Sufficient aggregated resources exist, but they are fragmented across hosts.
In such cases, vSphere HA uses vSphere DRS to try to adjust the cluster by migrating virtual machines to defragment the resources.
When a failover occurs, vSphere HA first checks whether resources are available on that host for the failover. If resources are not available, vSphere HA asks vSphere ____ to accommodate for these where possible.
DRS
