Page 192 - Cloud computing: From paradigm to operation

1 Framework and requirements for cloud computing

7 Functional requirements for a physical machine

7.1 Component requirements

7.1.1 Processing unit requirements

7.1.1.1 CPU requirements
– Virtualization instruction set: It is recommended that a physical machine supports a CPU
virtualization instruction set to improve the performance of CPU virtualization.
– CPU replacement: It is recommended that a physical machine supports substitution of CPU with
other CPUs to allow CPU upgrade or replacement of faulty CPUs.
– Multiple CPUs: It is recommended that a physical machine supports multiple CPUs to achieve higher
performance.
– Low power consumption of CPU: It is recommended that a physical machine supports low power
consumption of CPU to reduce the operational expenditure (OPEX).

7.1.1.2 Memory requirements
– Hardware-assisted memory virtualization: It is recommended that a physical machine supports
hardware-assisted memory virtualization to improve the performance of memory virtualization.
– Memory replacement: It is recommended that a physical machine supports substitution of memory
with other memories to allow memory upgrade or replacement of faulty memory.
– Memory reliability: It is recommended that a physical machine supports memory reliability using
memory redundancy and memory error correction technologies.
NOTE 1 – Memory reliability refers to technologies to improve the reliability of the physical machine by preventing
permanent loss of data or downtime caused by memory failure. One example is memory mirroring, as one
implementation of memory redundancy. Memory mirroring replicates and stores data on a different physical memory
within different channels simultaneously. If the primary physical memory failure occurs, subsequent read and write will
use the backup memory.
– Supporting various types of memory: It is recommended that a physical machine provides various
types of memory such as non-volatile and volatile memory depending on the CPU's memory usage.
NOTE 2 – Examples of CPU's memory usage with non-volatile and volatile types are booting up and storing temporary
data as main memory, respectively. Non-volatile type includes ROM and volatile type is classified into static random
access memory (SRAM) and dynamic random access memory (DRAM).
7.1.1.3 Storage requirements
– Multiple interfaces for storage: It is recommended that a physical machine supports interfaces of
storage for different media, such as magnetic storage, optical storage and semiconductor storage.
NOTE 1 – Examples of interfaces include integrated development environment (IDE), serial AT attachment (SATA), serial
attached SCSI (SAS), small computer system interface (SCSI), AT attachment (ATA), M.2 (formerly known as NGFF),
peripheral component interconnect express (PCI-E) and mini-serial AT attachment (mSATA).
– Storage replacement: It is recommended that storage in a physical machine supports substitution
of storage with other storages to allow external storage upgrade or replacement of faulty external
storage.
– Storage redundancy hardware: It is recommended that a physical machine supports storage
redundancy hardware.
NOTE 2 – An example of storage redundancy hardware is RAID card. RAID card is to support data storage virtualization
technology that combines multiple physical disk drive components into one or more logical units for the purposes of
data redundancy, performance improvement, or both.
– Storage hibernation: It is recommended that a physical machine supports hibernation of storages
without I/O for a long time to reduce energy consumption.
NOTE 3 – An example of storage hibernation is hard disk drive (HDD) hibernation. The HDD spins continuously at
5400/7200 revolutions per minute (RPM) consuming lots of power. During HDD hibernation, the HDD stops spinning to
reduce power consumption.

184