New-age Storage

Enterprise storage is among the hottest markets today, with new technologies cropping up, and many innovations being made on existing ones. From a one-to-one or direct-attached storage scheme, we moved to a many-to-one scenario, where storage became a separate entity on the network. This is known as the NAS (Network Attached Storage) model. The burgeoning need for more capacity and faster storage led to the concept of SAN (Storage Area Network), which creates a separate storage network based on an FC (Fiber Channel) backbone. Now, emerging technologies will even allow IP-based storage on your existing network infrastructure. Let’s look at these in more detail.

Though FC-based SAN technology is hot, it has some limitations. The first one is the distance in an FC-based network. Though you can take it up to 10 km, the high cost of fiber makes maintenance costs quite high. Another consideration is the high implementation cost of SAN itself. Finally, SAN is still an emerging technology. Standards are still being agreed upon, leading to proprietary SAN solutions from various vendors.

IP-based storage networking, another interesting emerging technology, uses your existing network infrastructure and TCP/IP for delivering storage traffic. One example of this is the new iSCSI standard under development, which will make existing SCSI standards work over TCP/IP. Majors like Adaptec, Cisco, and IBM have either already launched, or are in the process of launching iSCSI products (switches and routers). These can be used in conjunction with existing Ethernet devices to carry storage traffic. Future products are slated to replace Ethernet network devices altogether and the same iSCSI switch or router will carry both network and storage traffic. iSCSI works over Ethernet and TCP/IP, which has inherently been designed to carry small packets of data. It is less complex, easy to deploy, more robust, and data can be backed up to multiple locations spread over geographical boundaries.

Though initial costs of deployment of iSCSI are in the same range as a typical SAN establishment, run-time costs are much lower and even a sufficiently trained and qualified Ethernet network administrator can manage the setup. Another advantage is that with storage over IP, some inherent features of Ethernet like auto-fail over and load balancing are transported over to the storage traffic. However, with an FC-based network like SAN, significant re-wiring will be required.

In the long run, perhaps, another technology called Fiber Channel-over-IP could become more acceptable because it does block transfers, which are much faster than conventional IP-based transfers. It will be interesting to see how the storage market shapes up with all these technologies. Another catalyst is the Gigabit Ethernet, the market for which has started warming up.

Ashish Sharma