SAN characteristics
A SAN storage resource needs to be served by, but subject to a flexible, centralized management system with characteristics like smoothly scalable capacity allocations, transparent to the client operating system, capable of integrating legacy storage, adaptable to any SAN infrastructure, adaptable to the use of RAID storage, compatible with operating system security requirements, capable of providing full data redundancy, enhances application performance, minimal or no client-side software or driver, enhances high-availability of storage and data, no proprietary hardware requirements and open system software.
Such characteristics can be 'simplified' into eight main features, which are availability, scalability, performance, connectivity, manageability, connectivity, interoperability and end-to-end support.
Availability
Users or administrators concern most on full data and application availability. Data availability involves serviceability, component monitoring, automatic fault detection, isolation and recovery, online repairability, and complete system restoration after fixing a failure, beyond system and path redundancy. Application availability means having a detailed testing program that includes fast recovery from unexpected conditions caused by system component failures. To wrap it all up, SAN will achieve these goals through multiple levels of path and system redundancy and powerful backup and disaster-recovery software.
Scalability
This feature lets growth in capacity, performance, connectivity, and availability without involving continuing operations. A SAN configuration is expected to grow without adding complexity and without reduction on performance. Scalability comprises of adaptability and portability for applications.
Performance
SAN gives improvements on several levels of performance such as combining multiple simultaneous data paths, load-balance software, and dynamic path reallocation. There are other potential performance improvements but it relate to the design of admission-control mechanisms such as assuring bandwidth for high-priority data streams and time-dependant events. For overall performance enhancements, resource sharing, data sharing and Storage Resource Management (SRM) are used.
Connectivity
In a SAN environment, every network server can deal with all the storage on the network. This level of connectivity will allow sharing business-critical data between heterogeneous or diverse platforms.
Manageability
In administering networks, managing storage is one of the most significant costs. Increased manageability has become a main concern in all distributed network environments. Data management and SRM automate the processes of backup, restoration, configuration, monitoring, load balancing, diagnosing, and reporting. The degree to which a SAN can mix and automate some or all of these steps will decide its position in hierarchy of product classes.
Interoperability
A SAN contains many components, and the lack of recognized standards has lifted the interoperability issue to a high level of concern. The condition is for all these elements to dialog and mix pleasantly, to allow the user the greatest flexibility in the choice of products and vendors. The existing Fibre Channel standards are a prerequisite but are not sufficient to attain interoperability among devices from various vendors. In the short-term period, users will need vendors to guarantee and maintain interoperability. Storage Networking Industry Association (SNIA) is currently defining standards to ease this problem.
Security
SAN management must set in several levels of security to ensure complete access. So far, implementations that deal with access control are done through zoning and partitioning techniques.
End-to-end support
Switching to SAN from previous architecture is an important task. It is a task that most users or administrators are not prepared to handle. That is why vendors must help to plan, integrate, install and service the entire SAN infrastructure.