6.0.1
Table Of Contents
- vSphere Resource Management
- Contents
- About vSphere Resource Management
- Updated Information
- Getting Started with Resource Management
- Configuring Resource Allocation Settings
- CPU Virtualization Basics
- Administering CPU Resources
- Memory Virtualization Basics
- Administering Memory Resources
- View Graphics Information
- 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
Memory Virtualization Basics 5
Before you manage memory resources, you should understand how they are being virtualized and used by
ESXi.
The VMkernel manages all physical RAM on the host. The VMkernel dedicates part of this managed
physical RAM for its own use. The rest is available for use by virtual machines.
The virtual and physical memory space is divided into blocks called pages. When physical memory is full,
the data for virtual pages that are not present in physical memory are stored on disk. Depending on
processor architecture, pages are typically 4 KB or 2 MB. See “Advanced Memory Attributes,” on page 116.
This chapter includes the following topics:
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“Virtual Machine Memory,” on page 29
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“Memory Overcommitment,” on page 30
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“Memory Sharing,” on page 30
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“Types of Memory Virtualization,” on page 31
Virtual Machine Memory
Each virtual machine consumes memory based on its configured size, plus additional overhead memory for
virtualization.
The configured size is the amount of memory that is presented to the guest operating system. This is
different from the amount of physical RAM that is allocated to the virtual machine. The latter depends on
the resource settings (shares, reservation, limit) and the level of memory pressure on the host.
For example, consider a virtual machine with a configured size of 1GB. When the guest operating system
boots, it detects that it is running on a dedicated machine with 1GB of physical memory. In some cases, the
virtual machine might be allocated the full 1GB. In other cases, it might receive a smaller allocation.
Regardless of the actual allocation, the guest operating system continues to behave as though it is running
on a dedicated machine with 1GB of physical memory.
Shares
Specify the relative priority for a virtual machine if more than the reservation
is available.
Reservation
Is a guaranteed lower bound on the amount of physical RAM that the host
reserves for the virtual machine, even when memory is overcommitted. Set
the reservation to a level that ensures the virtual machine has sufficient
memory to run efficiently, without excessive paging.
VMware, Inc. 29