Comparing Virtualization Platforms
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Transcript Comparing Virtualization Platforms
PowerVM and VMware
What this presentation is
Basic Terms that can be used to discuss multiple forms
of virtualization
Concepts common to virtualization platforms that
make planning easier
Notable differences between virtualization platforms
that should be understood when planning
IMHO
What this presentation is not
In anyway comprehensive
Basic Terms and Common Things
Virtualization Basics
Virtualization Basics
Physical Capacity
The amount of resources physically present
Virtual systems have little or no visibility
Virtualization Basics
Hypervisor
Abstraction layer between physical hardware and virtual
systems
PowerVM – Firmware
VMWare - Software
Virtualization Basics
Accessible Capacity
Amount of resource that a virtual system can potentially
have access to
Also the amount of resource that a virtual system thinks
it has access to
PowerVM – Virtual CPUs
VMWare – Virtual CPUs
Virtualization Basics
Guaranteed Capacity
Amount of resource that a virtual system can have no
matter what other demands are placed on the physical
resources
Limiting factor that determines how many virtual
systems can be started
Cannot guarantee more resources than physically
present
PowerVM – Entitlement
VMWare - Reservation
Virtualization Basics
Limit
Maximum amount of resources that a virtual system can
access
PowerVM – Cap – Tied to guaranteed capacity
VMWare - Limit – Not tied to guaranteed capacity
Virtualization Basics
Priority
How resources are divided when demand is greater than
physical capacity
Only affects access to accessible resources above the
amount guaranteed
PowerVM – Priority Weight
VMWare – Shares
Virtualization Basics
Mobility
Ability to move virtual systems from one physical
hardware device to another with no disruption in service
to the virtual system
Independence from physical hardware
PowerVM – Live Partition Mobility (LPM)
VMWare - vMotion
Cluster vs. Host
VMWare – Cluster centric focus
PowerVM – Host centric focus
CPU
Scalability
Number of vCPUs supported for a single virtual system
Performance rating of physical hardware
Coscheduling and Processor Folding
Configuration flexibility
Adding/removing resources
Hot Add/Hot Plug
Threading Differences
Memory
Committed vs. Not Committed
VMWare
Transparent Page Sharing
Balloon Driver
PowerVM
Active Memory Sharing
Active Memory Expansion
Storage - Space
VMWare – Cluster/Pool Storage
Storage allocations are presented to all of the hosts
within a cluster and formatted with a proprietary file
Virtual system is a set of files within the filesystem
controlled by the hypervisor.
PowerVM – Direct Storage
Storage allocations are presented to VIO servers which
then proxy them to the virtual system (vscsi) or storage
allocations are presented directly to the virtual system
(npiv)
Virtual system directly formats and manages storage
Storage - Throughput
Multipathing support
Quality of Service (Storage IO Control)
Priority vs. Guarantee
Reverse order of application
PowerVM – Guarantee applied first then Priority Weight
VMWare – Shares applied first then Reservations
Performance Measurement
CPU
Contention for physical resources
PowerVM – Involuntary Context Switches
VMWare – CPU Ready
Performance Measurement
CPU
Measurements from inside the virtual system
PowerVM
PURR
Entitlement vs. Virtual Utilization
Performance Measurement
CPU
Measurements from inside the virtual system
VMware
Skew
Run Queue in single vCPU virtual systems
Performance Measurement
Memory
Tracking memory allocation and usage by virtual systems
PowerVM – N/A?
VMWare
Actively used
Shared
Balloon/vmmemctl
Swap
Consumed
Overhead
Performance Measurement
IO Measurement
PowerVM – NPIV configurations have a measurement
gap at the the physical HBA
Performance Measurement
Cluster Vs. Host Measurement
PowerVM – Virtual systems collect their own
performance information
VMWare – Hypervisor collects performance information