Storage Network Technologies – An Overview!

With the emergence of Internet, Big Data, Enterprise intranets, e-Commerce, business-to-business (B2B), ERP (Enterprise Resource Planning), data warehousing, rich media streaming, voice/video/data convergence, huge amounts of data is being generated. A typical data record has tripled over last 5 years. According to a study by IBM, 2.5 quintillion bytes of data are being written every day and 90% of global data has been created in the last two years alone and this will further keep on increasing.

For any corporate, just like it’s employees are one of the valuable assets,, data available has also become the most valuable asset. Effectively storing, accessing, protecting and managing critical data is new challenge faced by current IT departments.

Storage Technologies

The need to access and protect this data as strategic asset cannot be satisfied by traditional technologies like tapes. The inherent issues of tape media has resulted into supplemental storage or replacement of the tape media altogether. The current storage architecture is based on the network.

Downtime is the most critical factor for today’s businesses. The downtime costs are enormous and can cause service outage and customer dis-satisfaction. Federal mandates have further created stringent requirements for data security and high availability as per compliance standards.

The storage network technology has evolved into primarily three configurations : Direct Attached Storage (DAS), Network Attached Storage (NAS) and Storage Area Network (SAN)

Direct Attached Storage (DAS)

This is a traditional method of locally connecting storage devices to servers over direct communication path (known as buses) between server and storage device. It is a dedicated communication path separate from the network and access is provided by intelligent access controller (e.g. SCSI, SATA). When servers need more space, additional storage units are added. This method also allowed one server to mirror with another.

Network Attached Storage (NAS)

This is file level access storage architecture with storage units attached directly over LAN. It allows file-level access to heterogeneous computer systems. The additional layer exists to address shared storage files. This technology typically uses Network File System (NFS) or Common Internet File System (CIFS) both IP based protocols. The advantage of this type of system is that several servers can access the files stored on NAS storage device. The servers can be running on different platforms (Linux/Windows) but they all use same common IP protocols.

Storage Area Network (SAN)

Like DAS, SAN is connected behind the servers and not locally to a server. SAN provides block level access to a server as opposed to file-level access. One file contains several blocks and it provides random access to any block on the storage device. SAN’s provide high availability and robust business continuity for critical data environments. SAN’s are typically switched fabric architectures using Fibre Channel (FC) connectivity.

To create the SAN based storage architecture, the SAN Switch/Director is the key element. Each SAN storage unit is connected to each server via one or multiple SAN switches/directors which provide redundancy within the paths to the storage units. This provides additional paths for communication and eliminates one central switch as a single point of failure.

Fibre Channel connectivity (FCP) offers High Speed access to open and proprietary variants of mainframes. Ethernet has many advantages similar to Fibre Channel for supporting SAN’s. Fibre Channel over Ethernet (FCoE) allows FC traffic to flow across Ethernet based networks bringing convergence of storage and IP protocols.

SAN Over IP

As Ethernet based communication has reached 10GB, the convergence being possible to use standard IP based communication. SAN over IP has become less expensive alternative for small and medium sized organizations. For organizations who need very high speeds, FC and FCoE can be used. The technology such as Internet Small Computing System (iSCSI) is commonly used by small and medium enterprises as it less expensive. The other technology called InfiniBand is also widely used for SAN. Also these technologies provide required speed and also if architected properly provides all other benefits such as data security, fault tolerance and scalability. If the data has to be moved across these different technologies, the gateway solutions are available.

Conclusion:

In today’s world almost every business is software business, every business is run on software. So as computing power is important so is the storage. The increasing requirement of storage capacity, data security and 100% availability have put challenges on organizations for planning and creating their infrastructures. Storage technologies such as FC , FCoE , iSCSI, Cloud Based Storage and their interoperability is important. Finally, intelligent architecting of Computer and Storage using those storage technologies is the key to the success and continuous growth of the business.

About Author:

Praful Joshi, Technical Director – Lyra Infosystems

Praful comes with over 25 years of experience in Embedded, Automotive, and Telecom industries. His areas of expertise include Design & Development, Open Source Operating Systems, Consulting & Support, and Technical Solution Architecting in the areas of Embedded Systems, Networking, and Systems Software.