Résumé virtualisation

Computer systems:

• Tower
• Compact servers
• Rack-mounted
• Blade

Server clustering

• Multiple servers (nodes ) are brought together in a cluster to improve availability and performance.

Key requirements of a data center: manageability

• Availability
• Performance
• Data integrity
• Scalability
• Flexibility
• Security
• Availability

Virtualization:

It is the process of masking the underlying complexity of physical resources and presenting the logical view of these resources to services (Operating Systems, storage, networks, desktops).

• Server virtualization

• Storage virtualization

• Network virtualization

• Application virtualization

• Desktop virtualization

Compute virtualization:

It is a technique of masking or abstracting the physical compute hardware and enabling multiple operating systems (OSs) to run concurrently on a single or clustered physical machine(s).

Benefits of server virtualization:

Server consolidation

• Isolation => SECURITY + PERFORMANCE

• Encapsulation and mobility => PORTABILITY

• Enhanced disaster recovery

• Hardware independence: VM can be easily moved

• Reduced cost : CAPEX + OPEX (space, hardware, power, cooling, maintenance, etc...)

• Rapid deployment of new applications

Virtual machine manager : aka hypervisor

Monolithic hypervisor: uses hypervisor-aware device drivers.

Microkernel hypervisor: have an operating system acting as the root, hyperV case

Server virt Requirements: x86 Hardware Virtualization

-Paravirtualization: Guest OS is modified to become ‘aware’ that it is running within a svirtualized environment.

-Hardware-Assisted Virtualization

-Full virtualization

Storage virtualization

Evolution of storage technology:

      -DAS: Cheap option serves only one particular server, increases server capacity for backup and sometimes file sharing

       - NAS: Typically used for file sharing among multiple servers into a single storage device as well as for backup of data. Connection transfer from the servers to the NAS storage device can be an issue.

• SAN: A shared network of storage over a high-speed backbone network. Provides better performance and better reliability, but more expensive.

Benefits of Redundant Array of Independent Disks (RAID) storage technology:

-Improves storage system performance and provides data protection against drive failures.

Striping: spread data across multiple drives in order to use the drives in parallel: Speed Mirroring: Store the same data simultaneously on two different drives: fault-tolerance.

-Fibre Channel SAN (FC SAN): Offers data transfer speeds up to 16 Gbps

-Internet Protocol SAN (IP SAN): Re-utilize an existing IP-based network instead of building a new FC SAN infrastructure.

Define storage virtualization: Masking the underlying complexity of physical storage resources

and presenting the logical view of these resources to compute systems (via a virtualization

layer).

-Automated Storage Tiering (AST): A technique to establish a hierarchy of

different storage types for different categories of data that enables storing the right data

automatically to the right tier, to meet the service level requirements (e.g. degree of protection,

performance and cost)

*Network-based storage virtualization can be applied at 3 different layers:

o Block-level (at the SAN-level): virtualization layer creates an abstraction layer in the

SAN, between physical storage resources and virtual volumes on the virtualization

appliance at the network. Uses SCSI, FC or SATA protocols. Suited for transactional data.

o File-level (at the NAS/file server-level): enables users to use a logical path, rather than a

physical path to access files. File virtualization facilitates the movement of files between

the NAS systems. Uses CIFS or NFS protocols. Suited for shared file data.

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