6.7
Table Of Contents
- vSphere Resource Management
- Contents
- About vSphere Resource Management
- Getting Started with Resource Management
- Configuring Resource Allocation Settings
- CPU Virtualization Basics
- Administering CPU Resources
- Memory Virtualization Basics
- Administering Memory Resources
- Persistent Memory
- Configuring Virtual Graphics
- Managing Storage I/O Resources
- Managing Resource Pools
- Creating a DRS Cluster
- Using DRS Clusters to Manage Resources
- Creating a Datastore Cluster
- Initial Placement and Ongoing Balancing
- Storage Migration Recommendations
- Create a Datastore Cluster
- Enable and Disable Storage DRS
- Set the Automation Level for Datastore Clusters
- Setting the Aggressiveness Level for Storage DRS
- Datastore Cluster Requirements
- Adding and Removing Datastores from a Datastore Cluster
- Using Datastore Clusters to Manage Storage Resources
- Using NUMA Systems with ESXi
- Advanced Attributes
- Fault Definitions
- Virtual Machine is Pinned
- Virtual Machine not Compatible with any Host
- VM/VM DRS Rule Violated when Moving to another Host
- Host Incompatible with Virtual Machine
- Host Has Virtual Machine That Violates VM/VM DRS Rules
- Host has Insufficient Capacity for Virtual Machine
- Host in Incorrect State
- Host Has Insufficient Number of Physical CPUs for Virtual Machine
- Host has Insufficient Capacity for Each Virtual Machine CPU
- The Virtual Machine Is in vMotion
- No Active Host in Cluster
- Insufficient Resources
- Insufficient Resources to Satisfy Configured Failover Level for HA
- No Compatible Hard Affinity Host
- No Compatible Soft Affinity Host
- Soft Rule Violation Correction Disallowed
- Soft Rule Violation Correction Impact
- DRS Troubleshooting Information
- Cluster Problems
- Load Imbalance on Cluster
- Cluster is Yellow
- Cluster is Red Because of Inconsistent Resource Pool
- Cluster Is Red Because Failover Capacity Is Violated
- No Hosts are Powered Off When Total Cluster Load is Low
- Hosts Are Powered-off When Total Cluster Load Is High
- DRS Seldom or Never Performs vMotion Migrations
- Host Problems
- DRS Recommends Host Be Powered on to Increase Capacity When Total Cluster Load Is Low
- Total Cluster Load Is High
- Total Cluster Load Is Low
- DRS Does Not Evacuate a Host Requested to Enter Maintenance or Standby Mode
- DRS Does Not Move Any Virtual Machines onto a Host
- DRS Does Not Move Any Virtual Machines from a Host
- Virtual Machine Problems
- Cluster Problems
For each DRS cluster that the virtual machines being powered on belong to, there is a single
recommendation, which contains all the prerequisites (or no recommendation). All such cluster-specific
recommendations are presented together under the Power On Recommendations tab.
When a nonautomatic group power-on attempt is made, and virtual machines not subject to an initial
placement recommendation (that is, the virtual machines on standalone hosts or in non-DRS clusters) are
included, vCenter Server attempts to power them on automatically. If these power-ons are successful,
they are listed under the Started Power-Ons tab. Any virtual machines that fail to power-on are listed
under the Failed Power-Ons tab.
Example: Group Power-on
The user selects three virtual machines in the same data center for a group power-on attempt. The first
two virtual machines (VM1 and VM2) are in the same DRS cluster (Cluster1), while the third virtual
machine (VM3) is on a standalone host. VM1 is in automatic mode and VM2 is in manual mode. For this
scenario, the user is presented with an initial placement recommendation for Cluster1 (under the Power
On Recommendations tab) which consists of actions for powering on VM1 and VM2. An attempt is
made to power on VM3 automatically and, if successful, it is listed under the Started Power-Ons tab. If
this attempt fails, it is listed under the Failed Power-Ons tab.
Virtual Machine Migration
Although DRS performs initial placements so that load is balanced across the cluster, changes in virtual
machine load and resource availability can cause the cluster to become unbalanced. To correct such
imbalances, DRS generates migration recommendations.
If DRS is enabled on the cluster, load can be distributed more uniformly to reduce the degree of this
imbalance. For example, the three hosts on the left side of the following figure are unbalanced. Assume
that Host 1, Host 2, and Host 3 have identical capacity, and all virtual machines have the same
configuration and load (which includes reservation, if set). However, because Host 1 has six virtual
machines, its resources might be overused while ample resources are available on Host 2 and Host 3.
DRS migrates (or recommends the migration of) virtual machines from Host 1 to Host 2 and Host 3. On
the right side of the diagram, the properly load balanced configuration of the hosts that results appears.
vSphere Resource Management
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