XenServer

Xen is a hypervisor providing services that allow multiple computer operating systems to execute on the same computer hardware concurrently. This article will focus on "XenServer" (the Citrix Xen-based product that is now Open Source).

Glossary of XenServer-related terms

I will use the following terms, acronyms, abbreviations, etc. through my series of articles on XenServer-related information, programs, and technologies.

XC 

XenClassic

XS 

XenServer

slice 

a users Cloud Server in First Gen (also, instance, VM or server)

host 

physical server, which contains a hypervisor Xen or XenServer. Host and hypervisor are commonly used interchangeably.

VHD 

actual Virtual HDD file ends with this extension

VDI 

virtual disk image. A Virtual Hard Drive image record in XenServer

SR 

Storage Repository

PBD 

Physical Block Device (actual "/dev/sda" on host). The PDB is a connector object that represents the interface between a physical host and an attached storage repository (SR). A physical block device is responsible for storing the device configuration fields that are used to connect to, and interact with, a given storage target. It also manages the run-time attachment of a given storage repository to a given host.

VBD 

virtual block device. What XenServer calls what you "plug" into.

VIF 

Virtual Network interface for slice

LVM 

Logical Volume Management (software raid used in XC)

VM 

Virtual Guest Machine (slice/instance)

PIF 

Physical Network Interface

xe 

Xen Server commands start with this

xm 

Xen Classic commands start with this (http://linux.die.net/man/1/xm)

xl 

Command used to run some legacy XC utils in XS (e.g., xl list, xl console)

network 

virtual networks

pool 

a pool of physical hosts

API 

Application Programming Interface. Enables programmers to create application services by using an open application.

flavor 

A resource configuration for a server. Each flavor is a unique combination of disk, memory, vCPUs, and network bandwidth.

HTTP 

HyperText Transfer Protocol. The protocol that tells browsers where to find information.

image 

A collection of files for a specific operating system (OS) that you use to create or rebuild a server. You can create custom images from servers that you have launched. Custom images can be used for data backups or as "gold" images for additional servers.

REST 

REpresentational State Transfer. A style of architecture for hypermedia systems that is used for the World Wide web.

RESTful 

A kind of web service API that uses REST.

server 

A computer that provides explicit services to the client software running on that system. A server is a virtual machine (VM) instance in the Cloud Servers environment. To create a server, you must specify a name, flavor reference, and image reference.