Problems with standardisation in storage networking are leading businesses to abandon cross-platform IP initiatives to concentrate their spending on one supplier.
Firms are now looking to reduce the number of locations where they store data in an attempt to cut costs and boost security. This can be achieved by investing in high-end security and storage systems at a smaller number of datacentres as part of business continuity plans.
Several storage protocol options are available, the most popular being storage area networks. Sans have played a key role in enabling firms to share information in real-time, across different local departments and between corporate units across different continents.
A San is typically based on the Fibre Channel protocol, but can also use protocols such as asynchronous transfer mode, Fast Ethernet (100mbps) and Gigabit Ethernet, with 10 Gigabit Ethernet now here too.
Fibre Channel has a connectivity reach of only 10km and the maximum data throughput is only 2gbps. In the 1990s this performance was seen as very satisfactory and, in truth, was probably the only real solution for many. But the Fibre Channel protocol is straining as a result of businesses connecting more sites over greater distances, together with vastly increased amounts of data to push through and store.
The arrival of technologies such as Gigabit Ethernet means IT directors now have a viable alternative to Fibre Channel. Even though the first Gigabit Ethernet solutions were not as fast as Fibre Channel, their reach was potentially much further than the 10km limit.
Along with the greater distance it supports, Gigabit is a well-understood technology. The fact that corporates already rely on Ethernet technology for their basic networking means that a San built using 10 Gigabit Ethernet looks much more attractive to firms than Fibre Channel-based technology.
Analyst IDC has estimated that use of Gigabit Ethernet network connection ports will increase more than fivefold in 2004, so companies buying these ports will want to ensure their investment in Gigabit Ethernet is fully realised by adopting or expanding towards 10 Gigabit Ethernet for their storage needs.
The IP combination
The biggest shake-up in storage today is the widespread adoption of Internet Protocol and increased use of the internet. IP potentially makes the reach of a San infinite, therefore making it possible for companies to link datacentres cost effectively - not only between cities, but also across continents.
Gigabit Ethernet technology is combined with IP to form yet another new storage protocol called internet SCSI. This is now seen as the ideal way for companies to secure their stored and shared data over long distances. Following a painstakingly slow standards ratification process, commercial iSCSI products are now here.
Not surprisingly, take-up of this new storage technology has been slow. According to a recent survey of IT departments by supplier body the Storage Networking Industry Association (SNIA), fewer than 4% of users have begun to experiment with iSCSI. However, 25% of survey respondents expected to deploy iSCSI within the next year.
Protocol technology, whether it be Fibre Channel, Gigabit Ethernet or iSCSI, is only part of the problem IT directors face when implementing a San.
Technically it is still complicated to design and implement a San and many companies need third party help to make sure they build the resilience they need into the system.
One problem is that storage products from different manufacturers are incompatible, making it difficult to manage a storage infrastructure easily. Centralised management of a San through a single management interface increases efficiency. It is possible to manage and support hundreds of servers and devices as a single entity. This lowers the cost of storage management on a per unit basis, and increases the functionality available to network administrators - although for many companies this target has turned out to be difficult to achieve.
Progress has been made, albeit slowly, driven by the SNIA. The SNIA has developed a standard called SMI-S (Storage Management Interface Specification) for storage architecture which is designed to manage storage from different suppliers - and the major suppliers appear to be adopting it. SMI-S is a set of common models and protocols designed to let storage management applications control storage devices made by different hardware suppliers.
Supplier storage products
In February, as part of a raft of product launches around its information lifecycle management strategy, EMC said it would add support for the SMI to its management software and add SMI-S compliance to its Symmetrix and Clariion products.
Last October, Hitachi signed a deal with AppIQ, a storage management company, to integrate AppIQ's storage authority management software into its own Hicommand policy manager over the next two years.
Through the agreement, Hitachi's customers will gain the ability to manage devices using the Storage Management Initiative standard.
Although SMI-S has gained wider acceptance among suppliers and is becoming incorporated into products, users appear to be overcoming storage incompatibility by standardising on the products and services of one supplier.
John McArthur, group vice-president of storage research at IDC, said, "International companies are linking together datacentres for data availability, colla-borative working, or business continuity/disaster recovery.
"However, many cannot afford to manage the complexity, costs and potential risks associated with involving multiple storage suppliers and telcos. So, instead they are seeking a single trusted partner who can provide the complete storage network infrastructure."
One example of the type of service on offer is the recently formed alliance of Dell, EMC, Nortel Networks and BT. The firms are inviting customers to sample the long-distance business continuity network they have set up at Dell's European headquarters in Ireland.
Using the storage boxes and network switches from this alliance, customers can implement a San between large datacentres from between £105,000 and £385,000 (list price, including "gold level" 24x7 support).
The price of shifting the data through the right data pipe is additional to this hardware cost. The involvement of BT in this alliance shows that telecoms companies realise that the price of bandwidth has dropped so much they must move quickly to make up lost revenue by offering consultancy and support, both before and after the implementation of networks such as Sans.
- Sans can be based on Fibre Channel protocol, ATM, Fast Ethernet or Gigabit Ethernet
- Fibre Channel is short range and relatively slow; Gigabit Ethernet boasts a slightly longer range
- Internet Protocol can extend the reach of Sans to global distances
- The next big thing is iSCSI, a standard combining global Ethernet with IP.