The volume and value of enterprise data have been growing faster than the speed at which traditional backup company utilities have been increasing. Enterprises have become more dependent on their online systems and cannot ensure the availability of these data by relying only on traditional, network-bottlenecked, server-attached storage systems. Solutions to this problem have been offered by SAN technology, which provides enterprises with serverless zero-time-windows backup. In this new backup approach, backed-up data are removed to a secondary remote storage device, and the enterprise server becomes off-loaded, permitting high-performance continuous access to both applications and data.
Benefits of SANs
A SAN makes physical storage capacity a single, scalable resource and allows the flexible allocation of virtualized storage volumes (e.g., RAIDs, JBODs, and EMC, SUN, and DELL storage devices). The SAN can manage backup tasks that were a huge administrative and computer-resource burden under old storage architectures. The storage management cost savings can be higher than 80%. A cost-effective, scalable SAN enhances overall system performance. It can integrate legacy SCSI devices, which allows for increasing their system-wide effective usable capacity by up to 30%.
SAN applications cover the following areas of data transfer (Peterson, 1998):
(1) the externalization of data storage out of the server-SAN-attached-storage (SAS) and NAS with-SAN-interconnects network architectures;
(2) clustering, a redundant process that provides failover, high availability, performance, and scalability through the use of multiple servers as a data pipe and allows data storage resources to be shared;
(3) data protection solutions for backup, remote clustering, file mirroring, and replicating and journaling file systems by creating data storage redundancy on a dynamic basis;
(4) data vaulting, which is the process of transferring archived data to less expensive media;
(5) data interchange from one storage system to another or between different environments; and
(6) disaster recovery, which is similar to data interchange, moving copies of data offsite, and is built on remote vaulting (backup) processes or on remote array mirroring or clustering
The SANs architectures have been changed evolutionarily, adapting to new application demands and expanding capacities. The original fiber-channel-based SANs were simple loop configurations based on the fiber channel arbitrated loop (FC-AP) standard. Requirements of scalability and new functionality had transformed SANs into fabric based switching systems. Numerous vendors offered different solutions of problems based on fabric switching. As a result, immature standards created various interoperability problems. H
SAN technologies and solutions
The SAN infrastructures support multiple protocols, such as SCSI, SNMP, VI, ESCON/FICON, TCP/IP, and SSAIP, over a single physical connection. This unique capability provides the SAN system with a coupled functionality of an interface to storage devices and a server interconnect.
Crossroads Systems with a Storage Router
Infini Band technology has been successfully implemented by Crossroads Systems, Inc., which promotes storage solutions based on protocol-independent connectivity at Gigabit/s speeds and unparalleled manageability for various storage devices. The Crossroads storage routers support peer operations between storage devices and multiprotocol servers on fiber channel storage networks.
Other storage networking technologies
The following emerging technologies introduce new system architectural approaches in storage networking. SAN developers and users are trying to adapt them to a new enterprise environment that is characterized by host-level heterogeneous complexity, management flexibility, new TCP/IP network communication services, file-access protocol developments, and the repartitioning of the functionality of the file management systems.
SANs, networked high-speed infrastructures, enable e-business enterprises to improve significantly their 24 × 7 continuous scalable services. They have become a critical part of the enterprise network infrastructure. The above-considered technologies and effective SAN solutions allow companies to shift their focus from numerous IT infrastructure problems to the successful performance of their businesses and services.