The document discusses best practices for deploying Java applications in virtualized environments. It defines virtualization and describes types of virtualization including native and hypervisor virtualization. Benefits of virtualization include lower costs and easier administration, while potential disadvantages are reduced performance and specialized skills required. The document outlines how AMD technology can accelerate virtualization and discusses virtualizing the full Java application stack. It provides guidance on virtualization performance, resource allocation, bottlenecks, and consolidation.

1. Virtualizing a Virtual Machine
Azeem Jiva
Shrinivas Joshi
AMD Java Labs
TS-5227

2. Learn best practices for deploying Java EE
applications in virtualized environment
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3. Agenda
What is Virtualization?
Types of Virtualization
Why Virtualize?
Accelerating Virtualization
Java EE
Summary
Q&A
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4. What is Virtualization?
Platform Virtualization
• Abstraction of a computer
Resource Virtualization
• Abstraction or simplification of a resource
• Hide physical characteristics of computing resource
Provides consistent interface, regardless of resource
location
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5. Agenda
What is Virtualization?
Types of Virtualization
Why Virtualize?
Accelerating Virtualization
Java EE
Summary
Q&A
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6. Types of Virtualization
Overview
Native
• VMWare Workstation
• Microsoft® Virtual PC
• QEMU
• Virtual Box
• KVM
Hypervisor
• VMWare ESX Server
• XEN
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7. Types of Virtualization
Native
Virtualize Guest OS on a Host OS
• Linux® running on Windows®
• Windows running on Linux
Host OS not optimized for virtualization (usually)
Advanced virtualization features not available
Guest OS Guest OS Guest OS
Virtualization Software
Host Operating System
Hardware
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8. Types of Virtualization
Hypervisor
Virtualize Guest OS on a thin software layer
• Linux® running on ESX Server
• Windows® running on ESX Server
Hypervisor is optimized for virtualization
Advanced virtualization features are available and well
tested
Guest OS Guest OS Guest OS
Hypervisor
Hardware
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9. Agenda
What is Virtualization?
Types of Virtualization
Why Virtualize?
Accelerating Virtualization
Java EE
Summary
Q&A
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10. Why Virtualize?
Advantages
Not every application needs a full system
Easier to administer
• Need to do hardware maintenance?
• Move the virtualized OS disk to another system
Lower datacenter costs
Maintain legacy OSs and applications
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11. Why Virtualize?
Disadvantages
If Hypervisor crashes, all Guest OSes go with it
Performance
• With multiple Guest OSes, performance may suffer
• Usually 10%, can be as high as 20%
I/O-bound applications suffer
• Limit the number of I/O-bound applications
• Disk is the worst offender
Immature tools
Specialized skill set required
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12. Agenda
What is Virtualization?
Types of Virtualization
Why Virtualize?
Accelerating Virtualization
Java EE
Summary
Q&A
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13. Accelerating Virtualization
AMD-V™ Technology
Nested Page Tables
• Virtualized CR3 in hardware
Tagged Transition Look-Aside Buffer (TTLB)
• Assign ID to TLB entries
• Hardware knows which TLB entry belongs to which Guest OS
Device Exclusion Vector (DEV)
• Excludes devices from accessing memory
• Bit to include/exclude devices from accessing a page
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14. Agenda
What is Virtualization?
Types of Virtualization
Why Virtualize?
Accelerating Virtualization
Java EE
Summary
Q&A
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15. Java EE
Virtualizing a complete stack
Application changes not required
Most changes are at Hypervisor level
Java Virtual Machine can be Guest OS
• JRockit Liquid
Effects of Virtualization
• Performance
• Resource allocation
• Bottlenecks
• Consolidation
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16. Java EE
Performance
SPECjbb2005 performance slows down 10%
Use as few virtual CPUs as possible
• If application is single-threaded, use a single VCPU
Decrease processor-to-processor communication
If possible use less than 896 MB of physical memory for
Linux® Guest OS
• Different mapping techniques are used over 896 MB
Be prepared for decrease in performance
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17. Java EE
Resource Allocation
Three-tier testing on single system
Page sharing
• Sharing of guest memory pages
• Decreases host memory usage
• Decreases I/O bandwidth
Run the same Guest OS for increased page sharing
Move Guest OS from system to system
• Running application doesn’t know (or care!)
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18. Java EE
Bottlenecks
CPU constraints
• Guest OS requires all allocated CPUs be available
• Sum of allocated CPUs == physical CPUs
Memory constraints
• Sum of allocated memory == physical memory
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19. Java EE
Bottlenecks
Disk I/O constraints
• Apps (dB) that have large number of small read/writes severely
affected
• SAN is common, or at least use a separate disk
Network constraints
• Lots of small packets affect latency
• Dedicated NIC
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20. Java EE
Consolidation
Move Guest OS to single system when load is low
Increase CPU core count on the rise
• Eight cores common now
• Expect Sixteen cores to be common in two years
Not all applications can take advantage of that many cores
Run many Guest OSes on a single system
• Each application thinks it is on 1-4 processing cores
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21. Summary
Virtualization helps lower total cost of ownership
Slight performance hit, improved maintainability
Bottlenecks on I/O
Sharing of resources on single Host OS
Consolidate systems
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22. For More Information
Sites
• http://www.amd.com/virtualization
• http://developer.amd.com/
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23. Trademark Attribution
AMD, the AMD arrow logo and combinations thereof and AMD-V are trademarks of Advanced Micro Devices, Inc.
Microsoft and Windows are registered marks of Microsoft Corporation in U.S. and other jurisdictions. Linux is
registered trademark of Linus Torvalds.
©2008 Advanced Micro Devices, Inc. All rights reserved.
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24. Azeem Jiva
Shrinivas Joshi
AMD Java Labs
TS-5227
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