6.5.1
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
- 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
- Index
The following table shows the default CPU and memory share values for a virtual machine. For resource
pools, the default CPU and memory share values are the same, but must be multiplied as if the resource
pool were a virtual machine with four virtual CPUs and 16 GB of memory.
Table 2‑1. Share Values
Setting CPU share values Memory share values
High 2000 shares per virtual CPU 20 shares per megabyte of congured virtual
machine memory.
Normal 1000 shares per virtual CPU 10 shares per megabyte of congured virtual
machine memory.
Low 500 shares per virtual CPU 5 shares per megabyte of congured virtual machine
memory.
For example, an SMP virtual machine with two virtual CPUs and 1GB RAM with CPU and memory shares
set to Normal has 2x1000=2000 shares of CPU and 10x1024=10240 shares of memory.
N Virtual machines with more than one virtual CPU are called SMP (symmetric multiprocessing)
virtual machines. ESXi supports up to 128 virtual CPUs per virtual machine.
The relative priority represented by each share changes when a new virtual machine is powered on. This
aects all virtual machines in the same resource pool. All of the virtual machines have the same number of
virtual CPUs. Consider the following examples.
n
Two CPU-bound virtual machines run on a host with 8GHz of aggregate CPU capacity. Their CPU
shares are set to Normal and get 4GHz each.
n
A third CPU-bound virtual machine is powered on. Its CPU shares value is set to High, which means it
should have twice as many shares as the machines set to Normal. The new virtual machine receives
4GHz and the two other machines get only 2GHz each. The same result occurs if the user species a
custom share value of 2000 for the third virtual machine.
Resource Allocation Reservation
A reservation species the guaranteed minimum allocation for a virtual machine.
vCenter Server or ESXi allows you to power on a virtual machine only if there are enough unreserved
resources to satisfy the reservation of the virtual machine. The server guarantees that amount even when the
physical server is heavily loaded. The reservation is expressed in concrete units (megaher or megabytes).
For example, assume you have 2GHz available and specify a reservation of 1GHz for VM1 and 1GHz for
VM2. Now each virtual machine is guaranteed to get 1GHz if it needs it. However, if VM1 is using only
500MHz, VM2 can use 1.5GHz.
Reservation defaults to 0. You can specify a reservation if you need to guarantee that the minimum required
amounts of CPU or memory are always available for the virtual machine.
Resource Allocation Limit
Limit species an upper bound for CPU, memory, or storage I/O resources that can be allocated to a virtual
machine.
A server can allocate more than the reservation to a virtual machine, but never allocates more than the limit,
even if there are unused resources on the system. The limit is expressed in concrete units (megaher,
megabytes, or I/O operations per second).
CPU, memory, and storage I/O resource limits default to unlimited. When the memory limit is unlimited,
the amount of memory congured for the virtual machine when it was created becomes its eective limit.
vSphere Resource Management
12 VMware, Inc.