Virtualization Supplemental Material beyond the textbook

What is Virtualization? The term virtualization is used very broadly in the computing industry can refer to: Hardware, software, storage, data, networks, etc. E.g. a hard drive partitioned into multiple virtual drives, a virtual LAN or a virtual private network Virtualization in our context is more specifically known as Platform Virtualization, the idea that the hardware platform will be virtualized to support many operating systems

What is Platform Virtualization? Platform Virtualization is often referred to as Server Virtualization because servers were the first target to virtualize (largely for money savings) Platform Virtualization also includes Desktop Virtualization, which is increasingly used as companies look for ways to cut their PC procurement and operating budgets

What is Virtualization? Virtualization is the idea that one computer can run multiple operating systems concurrently This idea is not new – mainframes have been providing virtualization capabilities for over 40 years Increases in computing power in Intel architecture computers is making virtualization very important

Hypervisor A hypervisor, also called virtual machine monitor (VMM), is a computer software/hardware platform virtualization software that allows multiple operating systems to run on a host computer concurrently. The base computer is known as the “host”, and the operating systems running on the host are known as “guests”

Types of Virtualization Type 1: Also referred to as native or bare-metal. Software systems that run directly on the host's hardware as a hardware control and guest operating system monitor Type 2: Software applications running within a conventional operating system environment

7 Type 1 Virtualization Type 2 Virtualization

Why Virtualize? Modern hardware has enormous processing capabilities (current Intel Xeon chips have 8 CPU cores supporting 2 threads per core; a server may have 4 of these) Consolidating servers saves electricity, cooling costs, and rack space in the server room Saving electricity means a lower carbon footprint, important to companies as they assess their environmental impact Run different OS’s simultaneously on one computer Disaster Recovery planning can be simplified by using virtualized operating systems

Example: Consolidation You have 20 existing SERVER computers –Each with two 3GHz CPUs –Each with 4 GB RAM –Each need about 500 GB disk space Propose a replacement plan using virtualization –Replace with servers that have 16 2 GHz CPU cores –How many physical computers? –How much RAM? –How much disk space?

Example: Consolidation Total processing power of the existing servers is 20 * 2 * 3GHz = 120 GHz –Total RAM of existing servers is 20 * 4 = 80 GB RAM –Total Disk of existing servers is 20 * 500 GB = 10 TB If a new server has 16 * 2 GHz = 32 GHz processing, we need about 4 new servers with 20GB RAM each and 2.5 TB disk each to replace the existing servers –Important – if you were really doing this, make sure you purchase one spare server!

Example: Electrical Savings Original 20 computers consume 250 Watts, new computers EnergyStar rated and consume 240 Watts Total annual energy consumption in KW hours = # servers * Watts consumed * 365 days * 24 hours / 1000 Total annual energy cost = Total annual KW hours * KW hour cost (the average US cost of a KW hour is ten cents) Original 20 computers: –Annual KW hours = 20 * 250 * 365 * 24 / 1000 = 43,800 KWh –Annual energy cost = 43,800 * $0.10 = $4,380 New 4 computers: –Annual KW hours = 4 * 240 * 365 * 24 / 1000 = 8,410 KWh –Annual energy cost = 8410 * $0.10 = $841

Disaster Recovery Servers fail due to Software: after installing patches or new software applications Hardware: a piece of hardware fails and the machine stops In a traditional computer, these failures may require reloading the operating system and applications, or rebuilding the hardware In a virtualized environment, the entire guest OS server exists as a file. This means if a server fails due to Software: you can simply replace the file with a recent copy from backup and restart the guest OS Hardware: you can move the file to another computer and start the guest OS

Estimating Effects of Virtualization 1.Estimate resources being replaced as: Processing Capacity per PC (CPUpc) * No. of PCs (#PC) = Required CPU processing speed (CPUr) RAM per PC * No. of PCs = required RAM (RAMr), and Disk storage per PC * No. of PCs = Disk Storage (HDr) required Adjust as needed – room for growth? Idle resources? 2.Estimate No. of server machines (SMr) needed as: CPUr / CPU Capacity per server machine (CPUsm) 3.Estimate RAM required per server machine as: RAMr / SMr 4.Estimate Hard Disk required per server machine as: HDr / SMr 5.Add server machine(s) (SMft) needed for fault-tolerance to get final count of server machines required -> SMrf = SMr + SMft 13