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
ESXi virtual machines can incur two kinds of memory overhead.
n
The additional time to access memory within a virtual machine.
n
The extra space needed by the ESXi host for its own code and data structures, beyond the memory
allocated to each virtual machine.
ESXi memory virtualization adds little time overhead to memory accesses. Because the processor's
paging hardware uses page tables (shadow page tables for software-based approach or two level page
tables for hardware-assisted approach) directly, most memory accesses in the virtual machine can
execute without address translation overhead.
The memory space overhead has two components.
n
A fixed, system-wide overhead for the VMkernel.
n
Additional overhead for each virtual machine.
Overhead memory includes space reserved for the virtual machine frame buffer and various virtualization
data structures, such as shadow page tables. Overhead memory depends on the number of virtual CPUs
and the configured memory for the guest operating system.
Overhead Memory on Virtual Machines
Virtual machines require a certain amount of available overhead memory to power on. You should be
aware of the amount of this overhead.
The following table lists the amount of overhead memory a virtual machine requires to power on. After a
virtual machine is running, the amount of overhead memory it uses might differ from the amount listed in
the table. The sample values were collected with VMX swap enabled and hardware MMU enabled for the
virtual machine. (VMX swap is enabled by default.)
Note The table provides a sample of overhead memory values and does not attempt to provide
information about all possible configurations. You can configure a virtual machine to have up to 64 virtual
CPUs, depending on the number of licensed CPUs on the host and the number of CPUs that the guest
operating system supports.
Table 6‑1. Sample Overhead Memory on Virtual Machines
Memory (MB) 1 VCPU 2 VCPUs 4 VCPUs 8 VCPUs
256 20.29 24.28 32.23 48.16
1024 25.90 29.91 37.86 53.82
4096 48.64 52.72 60.67 76.78
16384 139.62 143.98 151.93 168.60
vSphere Resource Management
VMware, Inc. 34