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CSCI 330 Virtualization

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Application Virtualization using a software virtualization layer to encapsulate ... RAID and volume managers combine many disks into one large logical disk. ... – PowerPoint PPT presentation

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Title: CSCI 330 Virtualization


1
CSCI 330Virtualization
  • Spring, 2009
  • Doug L Hoffman, PhD

2
Outline
  • Parallelism and Virtualization
  • Types of Virtualization
  • Process Virtualization
  • Resource Virtualization
  • Uses for Virtualization
  • Summary

3
Style of Parallelism
More Flexible, More HW Control
Simpler Programming model, Less HW Control
Data Level Parallel (Same operation lots of data,
1 PC)
Inst. Level Parallel (Different operations lots
of data, 1 PC)
Thread Level Parallel (Different operations lots
of data, N PCs)
Separate address spaces
Single addressspace
4
Virtualization Definition
In computing, virtualization is a broad term that
refers to the abstraction of computer
resources. One definition is that Virtualizatio
n is a technique for hiding the physical
characteristics of computing resources from the
way in which other systems, applications, or end
users interact with those resources. This
includes making a single physical resource (such
as a server, an operating system, an application,
or storage device) appear to function as multiple
logical resources or it can include making
multiple physical resources (such as storage
devices or servers) appear as a single logical
resource.
5
Two Broad Categories
  • Platform virtualizationthe simulation of whole
    computers.
  • IBMs VM/CMS 370
  • VMware
  • Xen
  • Resource virtualizationthe simulation of
    combined, fragmented, or simplified resources.
  • Virtual File Systems
  • VLANs

6
Platform Virtualization
CSCI 330 Computer Architecture
7
Platform Virtualization
  • The original sense of the term virtualization,
    dating from the 1960s, is in the creation of a
    virtual machine.
  • The term virtual machine apparently dates from
    the experimental IBM M44/44X system.
  • Platform virtualization is performed on a given
    hardware platform by host software (a control
    program), which creates a simulated computer
    environment, a virtual machine, for its guest
    software.
  • The guest software, which is often itself a
    complete operating system, runs just as if it
    were installed on a stand-alone hardware
    platform.
  • Typically, many such virtual machines are
    simulated on a single physical machine, their
    number limited only by the hosts hardware
    resources.

8
Platform Virtualization
  • There is no requirement for a guest OS to be the
    same as the host one.
  • The guest system often requires access to
    specific peripheral devices to function, so the
    simulation must support the guest's interfaces to
    those devices. For example
  • Hard disk drive
  • CD/DVD drive.
  • Network interface card.

9
Implementing Platform Virtualization
  • Application Virtualizationusing a software
    virtualization layer to encapsulate a desktop or
    server application from the local operating
    system. The application still executes locally
    using local resources. Example Wine.
  • Emulation or simulationthe virtual machine
    simulates the complete hardware, allowing an
    unmodified "guest" OS for a completely different
    CPU to be run. Can be very Slow!
  • Native virtualizationthe virtual machine
    simulates enough hardware to allow an unmodified
    "guest" OS (one designed for the same CPU) to be
    run in isolation.

10
Implementing Platform Virtualization
  • Hardware enabled virtualizationthe hardware
    provides architectural support that facilitates
    building a virtual machine monitor and allows
    guest OS to be run in isolation. In 2005, Intel
    and AMD provided additional hardware to support
    virtualization.

11
Resource Virtualization
CSCI 6380 Advanced Computer Architecture
12
Types Of Resource Virtualization
  • Computer clusters, grid computing, and virtual
    servers use the above techniques to combine
    multiple discrete computers into larger
    meta-computers.
  • Partitioning or splitting of a single resource
    (usually large), such as disk space or network
    bandwidth, into a number of smaller, more easily
    utilized resources of the same type. This is
    sometimes also called "zoning," especially in
    storage networks.
  • Resource aggregation, spanning, or concatenation
    combines individual components into larger
    resources or resource pools.

13
Resource Virtualization
  • Virtual memory, usually providing a different
    virtual address space for each application, which
    allows uniform, contiguous addressing of
    physically separate and non-contiguous memory
    areas.
  • RAID and volume managers combine many disks into
    one large logical disk.
  • I/O virtualization, the ability to run any I/O
    device on any server at any time and migrate that
    I/O device from server to server as needed, such
    as IBM Virtual I/O Server (VIOS).

14
Resource Virtualization
  • Storage Virtualization completely abstracts
    logical storage from physical storage, and is
    commonly used in SANs.
  • The physical storage resources are aggregated
    into storage pools, from which the logical
    storage is created.
  • Multiple independent storage devices, which may
    be scattered over a network, appear to the user
    as a single, location-independent, monolithic
    storage device, which can be managed centrally.

15
Resource Virtualization (continued)
  • Channel bonding and network equipment use
    multiple links combined to work as though they
    offered a single, higher-bandwidth link.
  • Virtual Private Network (VPN), Network Address
    Translation (NAT), and similar networking
    technologies create a virtualized network
    namespace within or across network subnets.

16
Resource Virtualization (continued)
  • All of these techniques can be combined into a
    single virtual environment called a Virtual Data
    Center.

17
Summary
CSCI 330 Computer Architecture
18
And in Conclusion
  • Virtualization can be applied to all aspects of
    computers
  • Processors (i.e. virtual machines).
  • Networks (VLANS and bandwidth partitioning).
  • Storage (SAN, iSCSI, NAT etc).
  • The performance impact of virtualization can vary
    widely.
  • Emulation can be really slow
  • Hardware assisted VMs can be quite fast.
  • Virtualization in not a panacea.

19
Next Time
  • More Virtualization
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