Glossary

ballooning
A process that allows the hypervisor to reclaim physical memory pages by forcing the virtual machine operating system to flush memory pages to disk.
bandwidth
A measure of network performance defined by the amount of data that can travel through the network over a period of time. Typically given in bits per seconds.
bare-metal
A computer server without any operating system software installed.
BCDR
Business Continuance and Disaster Recovery. An availability topic area that covers how businesses can protect their business-critical processing from disasters, natural and man-made, that would otherwise destroy or significantly interrupt service from the datacenter.
bridged network
A connection type that allows a virtual machine adapter to have a direct connection to the physical network with a unique IP address.
CIFS
Common Internet File System is similar to NFS but focused on Microsoft Windows environments.
clone
An exact copy of a virtual machine. Once cloned, the new virtual machine still needs final customization to ensure a unique identity.
CNA
Converged Network Adapter. A single network adapter that supports multiple network-protocol types, usually at much greater bandwidths than older NICs.
compression
A memory optimization technique that compresses memory pages and stores them in a designated cache in physical memory, rather than swap them from memory to disk storage.
consolidation
The practice of condensing multiple physical servers into one server through the use of virtualization.
consolidation ratio
A measure of consolidation calculated by counting the number of virtual machines on an individual server.
containment
The practice of deploying new applications on virtual machines, rather than buying, provisioning, and deploying new physical server hardware.
core
Microprocessors come in packages that contain one or more processing units. Each individual processing unit is a core.
CPU
Central Processing Unit. The core or brain of a computer where the user and system commands are executed. Today's computers use microprocessor technology, and the term processor is often used interchangeably with CPU.
daemon
A UNIX or Linux program that runs as a background process. Daemons typically perform certain system tasks such as cron (crond), the system scheduler, or managing the ftp capabilities (ftpd).
DAS
Direct Attached Storage. The disk drives that are internal to a physical computer.
data center
A large computer room, an entire floor in a building, or a separate building outfitted and dedicated to the health and well-being of a company's computing infrastructure.
deduplication
A storage technology that compresses data and reclaims disk storage space by removing duplicate copies of information. Only one copy is retained and pointers to that copy replace the additional duplicates. Deduplication can be done on a byte, block, or file level.
DHCP
Dynamic Host Configuration Protocol is a widely used standard that allows servers to assign IP addresses to computers and other devices on a network.
DMZ
A network area outside of a company's firewall that connects to the Internet. Few resources, typically web servers, are kept there. They are hardened against malicious attacks, keep little information of value, and connect to the protected network through a firewall.
Fibre-Channel
An industry standard protocol defined for connecting Storage Area Networks to computers.
FT
Fault Tolerance. Hardware and/or software solutions and implementations that allow a server to lose one or more components to a failure without data loss or service interruption.
guest
A virtual machine, or VM. Called a guest because it runs on a host server.
HA
High Availability. Hardware and/or software solutions and implementations that provide greater uptime and resiliency for a computing infrastructure.
HBA
Host Bus Adapter. Also called a host adapter, it is a hardware device that connects a computer to either a network or a storage network. Originally associated with Fibre-Channel connectivity.
HID
Human Interface Device is a broad definition for a class of computer peripheral devices that either receive or deliver information to humans. Examples of these would be, but are not limited to, mice, touchpads, and joysticks. Newer candidates are Wii remotes and Kinect for Xbox.
host
A physical server that supports virtual machines, or guests.
hyper-threading
An Intel microprocessor technology that improves performance by making more efficient use of the processing scheduling—effectively scheduling two threads of work where there was only one in the past.
hypervisor
Originally called a Virtual Machine Manager, it is a layer of software that is installed either between an operating system and the virtual machines or directly onto the hardware, or “bare-metal,” and provides the environment in which the virtual machines operate.
IP address
Internet Protocol address. The unique 32-bit number that identifies a computer or other device on a network. Traditional notation breaks the 32 bits into four 8-bit, or 1-byte, segments. Each byte is converted to a decimal number and the four are separated by periods—e.g., 192.168.000.001.
iSCSI
Internet Small Computer System Interface is the industry standard that defines how storage devices connect and transfer data to computers by sending the SCSI commands over Ethernet networks.
ISO image
A data file in an industry standard format that contains the exact image of an optical disc, like a CD or a DVD. They are used in this context to contain operating system or application files, usually for installation.
Linux
An open-source operating system that is a UNIX derivative. Usually available for low or no cost, Linux runs on a wide variety of hardware, including mainframe computers, servers, desktops, mobile devices, and other commercial appliances such as cable/satellite boxes, and video game consoles.
load balancer
A hardware or software appliance that balances traffic from multiple sources, preventing one pathway from being overloaded. Load balancers can also redirect traffic in the event of a pathway failure.
memory overcommit
The ability of a hypervisor, through the use of memory management optimizations, to allocate more virtual memory to its virtual machines than the amount of physical memory in the host on which it resides.
modem
A device that turns digital signals into analog signals and back again. A modem allows a user on one computer to connect and share data with a second computer by using a telephone line as the transfer medium. The base technology has evolved and is still in wide use today.
multicore
A microprocessor that contains more than one processing unit.
multipathing
Having more than one path available from data storage to a server by having multiple I/O controllers, network switches, and NIC cards.
NAS
Network Attached Storage is usually disk storage that is connected to one or more computers across a network by a file-based protocol, such as CIFS or NFS. As a file-based system, Network Attached Storage has file systems created and is managed external to the computer systems it supports.
NAT
Network Address Translation. A connection type that allows a virtual machine to share an IP address on the physical network with other virtual machines. Each virtual machine has a unique local address that is translated to the shared address for outbound traffic, and back again for inbound traffic for proper data delivery.
network switch
A device that connects computers, printers, file servers, and other devices, allowing them to communicate efficiently with each other. In some ways, switches create and define the networks that they manage.
NFS
Network File System is an open industry protocol standard that is typically used for computers to access Network Attached Storage systems.
NIC
Network Interface Card. A device that allows a computer to connect to a network. Also called a network adapter.
NTP
Network Time Protocol is an open standard that defines and implements a computer's ability to synchronize with Internet time servers, or with other servers.
OVF
Open Virtualization Format. A platform-independent industry standard that defines a format for the packaging and distribution of virtual machines.
P2V
Shorthand for Physical to Virtual. The manual or automated process that transfers the data on a physical server into a virtual machine. The data includes the operating system, applications files, and all data files.
page sharing
A memory optimization technique in which identical pages in memory are stored only as a single copy and shared between multiple virtual machines. Also works for identical pages in one virtual machine. Similar to disk storage deduplication.
paging
The process that computers use to copy blocks, or pages, of data from disk to memory and back again.
resource pool
An aggregation of resources that permits a virtualization administrator to allocate resources to individual virtual machines, groups of virtual machines, or groups of people.
RHEL
Shorthand for Red Hat Enterprise Linux. Red Hat is one of the leading providers of Linux distributions, and it makes its profit from support rather than license sales. Enterprise Linux is one edition of its offerings.
right-size
The process of configuring a virtual machine to have enough resources for good performance with enough overhead to handle periodic spikes and some growth without vastly over-allocating resources that would be wasted.
SAN
Storage Area Network. A combination of networking resources and disk arrays that provides data storage for computers. Multiple computers will access the SAN, which is external to the physical (or virtual) servers.
SCSI
Small Computer System Interface is the industry standard that defines how storage devices connect and transfer data to computers.
SMP virtualization
Symmetric Multiprocessing. A computer architecture that provides enhanced performance through the concurrent use of multiple processors and shared memory.
snapshot
A snapshot is a set of files that preserve the state of a virtual machine at a given point in time so you can repeatedly revert back to that given state. A virtual machine can have multiple snapshots.
swap space
Disk space reserved for memory pages to be written to in the event that not enough memory is available in the virtual (or physical) machine for the work that needs to be done.
template
A virtual machine that is used as a mold for a commonly used configuration. Once deployed from a template, the virtual machine still needs final customization, such as being given a unique system name and network information.
USB
Universal Service Bus, or USB, is an industry standard for connecting external devices to a computer. The standard defines the physical connections as well as the capabilities for the disparate devices it can support. In addition to data transfer, USB devices can draw electricity from the computer they are connected to for operational power or, in the case of mobile devices, to recharge their internal batteries.
vCPU
A virtual CPU. The virtual representation of a computer processor.
VM-affinity (and anti-affinity)
VM-affinity rules link together two or more virtual machines so they reside on the same virtualization host. Anti-affinity rules ensure that two machines do not reside on the same virtualization host. Live migration, automatic and manual, as well as high-availability recovery, will respect these rules.
VMware tools
A combination of device drivers and processes that enhance the user's experience with the virtual machine, improve virtual machine performance, and help manage the virtual machine. VMware tools are specific to VMware, but other virtualization vendors provide similar suites.
virtualization
The process by which physical servers are abstracted into software constructs that, from their user's standpoint, appear and behave identically to their physical counterparts.
virtual machine, or VM
A container that runs a guest operating system and applications in a software abstraction of a physical server. A powered-off virtual machine is merely a set of files that comprise and describe the virtual hardware and the data that make up the virtual machine.
..................Content has been hidden....................

You can't read the all page of ebook, please click here login for view all page.
Reset
3.138.122.4