Page 278 - Cloud computing: From paradigm to operation

1 Framework and requirements for cloud computing

I.1.1 Infrastructure sub-layer

This sub-layer consists of the following 3 parts:
– The storage infrastructure is composed of common used storage devices such as fibre channel
storage devices, NAS and Internet small computer system interface (iSCSI) [b-IETF RFC 3720] storage
devices, as well as some related supporting appliances, such as switches for storage. Storage
infrastructure will typically consist of several distributed working nodes to support high availability
and reliability. A working node can include a virtual volume management element, an NAS and a
distributed file system (DFS) device. Another type of working node can include a virtual volume
management element, a SAN and a block control device.
– The backup infrastructure is composed of a physical type library, a virtual type library, a database
and related software.
– The infrastructure monitor cluster is composed of many servers which manage and monitor all kinds
of storage and backup devices, repair related links and check the redundancy and carry out
centralized management. It can include a global schedule function to provide the resources location
in the storage infrastructure depending on the received accessing requests and associated
requested resources. The servers typically support distributed hash table (DHT) networking to
provide a general accessing interface for name space management, load balance, metadata
management, routing management and duplication management. The infrastructure monitor
cluster can access virtual volume management elements of the storage infrastructure to realize
unified volume management and policy management.
I.1.2 Presenting sub-layer

This sub-layer is the core of the service logic of the cloud storage system. It provides several storage services,
such as services based on SAN or NAS, as well as backup disaster recovery services.

SAN and NAS-based services provide key storage services for the management of cloud storage, detection
and repair of the faulty links, status monitoring and QoS.

Backup disaster recovery services supply high-level data protection making unnecessary the use of a
specialized disaster recovery network.

I.1.3 Access sub-layer

This sub-layer consists of storage-based application interfaces, network access equipment, user identification
functions and other relevant access functions. Once authenticated and authorized, users make use of the
cloud storage services, such as those based on the network file system (NFS) [b-IETF RFC 3530] or iSCSI [b-
IETF RFC 3720].
The access sub-layer connects users to the presenting sub-layer through the use of private or public
networks.

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