Storage Area Networks
A Storage Area Network or SAN is an architecture that is utilized to connect storage to servers so that the storage appears as locally attached to the server operating system or OS. A SAN typically has its own network of storage devices that are not accessible through the public network.
A SAN alone does not provide file level abstraction, only block level operations. However file systems built on top of SANs do provide this level of abstraction.
Historically, a Direct-Attached Storage or DAS approach to IT infrastructure created islands of storage with each disk array dedicated to a server. A SAN consolidates such islands of storage together into a consolidated pool of storage that can be accessed by many servers using a high-speed network.
The current generation of intelligent SANs offer an improved architecture, robust feature set, and many end user benefits over traditional SANs. Detailed information about each block of data provides unprecedented system intelligence to dynamically store, recover, and manage data. Storage Virtualization allows for the complete separation of the logical storage that is presented to the server and the actual physical storage on the array. The resulting benefits are as follows:
Automated Tiered Storage – Intelligent software classifies and migrates data at a block level to the optimum tier of storage based on actual usage. The most active blocks then reside on high-performance SSD or FC drives, while less active blocks of data automatically move to lower cost, high capacity SAS or SATA drives.
Advanced Thin Provisioning – Thin Provisioning provides for dramatically better storage utilization over traditional SANs. Thin provisioning completely separates storage allocation from storage utilization, allowing end users to allocate any size storage volume up front, yet only consume physical capacity when the data is actually written.
Continuous Data Protection - With intelligent snapshot capability an end user can take an unlimited number of space efficient snapshots to speed the local recovery of lost or deleted files. Once an initial snapshot of a volume is taken, only incremental changes in the data need to be captured.
Open Agile Hardware – Intelligent SANs are now being built on flexible, industry standard, non-proprietary hardware platforms that can scale without downtime. Rip and replace technology is being replaced with technology that allows for the continual adoption of new technologies and is built for persistence not obsolescence.
Remote Thin Replication – Space efficient snapshots can be replicated between local and remote sites for a cost effective disaster recovery solution. After initial synchronization, only incremental changes in data are replicated on an ongoing basis.
Easy-To-Use Management Interface – Current generation SAN GUIs provide a unified, point and click interface that cuts administration time and eliminates the need for specialized administrative SAN skills.
Improved Capacity Planning – Current generation SANs allow the end user to create high performance, highly efficient volumes in seconds without allocating drives to a specific server, without complicated capacity planning and without performance tuning. An end user can dynamically change and scale a virtualized pool of store with no disruption or downtime.