-- Vtesse Networks and Hitachi Data Systems break data transmission records
4 April 2003 Stockholm, Sweden -- Vtesse Networks and Hitachi Data Systems (HDS), with the support of Transmode Systems and Nishan Systems, have demonstrated a synchronous SAN application over 600km.
The partners say this distance is six times further than it has previously been thought possible for a data application to be synchronously transmitted over a Fibre Channel link.
HDS's TrueCopy 9900 disk storage system was employed to synchronously update an Oracle database over a Vtesse Networks Gigabit Ethernet transmission system, using Transmode CWDM equipment and single-mode fibre supplied by Corning.
A Nishan Systems IPS 3300 multi-protocol switch converted native Fibre Channel from the HDS equipment into Gigabit Ethernet and thereby remove the usual link length restrictions of the Fibre Channel format.
Conventional Fibre Channel transmission poses serious restrictions on realisable link lengths for synchronous SAN applications such as data replication using disk mirroring.
Throughput capacity of a Fibre Channel system falls very quickly over link lengths greater than 100km due to the inherent time delay, or latency, of the fibre link length and insufficient buffering in Fibre Channel fabric switches.
This reduction in throughput capacity slows the operation of SAN applications. However, the trial demonstrates that successful operation involving acceptable performance degradation can be achieved over distances of up to 600km.
"This trial not only shows that the inherent length restrictions of Fibre Channel can be overcome - it also demonstrates that synchronous data replication can now be realised between data centres anywhere within the UK," said Aidan Paul, CEO of Vtesse Networks.
"Another benefit is that more cost effective and widely available Gigabit Ethernet networks can be used to interconnect SAN applications. This arrangement reduces costs as well as increases the range of options open to companies requiring data replication and protection over national rather than regional distances."
"This application demonstrates the advances that CWDM technology has made over the past year," said Isaac Olasoko, CEO of Transmode Systems.
"In the past, CWDM had been thought of as a technology that was restricted to short-reach Metro Access applications. Now, the cost and operational advantages that CWDM brings to access networks can be extended to regional and even national networking."
The trial arrangement used the Nishan IPS 3300 IP storage switches to convert the Fibre Channel format from the HDS storage system into Gigabit Ethernet and then transmit this format natively over the Transmode CWDM system.
The Nishan equipment uses frame buffering and powerful data processing techniques to reduce the length restrictions caused by the frame-by-frame acknowledgement methods used in Fibre Channel and so extend the length capability to several thousand kilometres without losing the advantages of true synchronous operation.
The Oracle database application, involving simple row insertions, was chosen specifically by HDS to simulate a real life data replication requirement of a major UK financial institution.
Timings for a representative Oracle database operation involving 82.5Gbytes of data were measured both for local operation with zero link length and over a range of link distances between 50 to 600km. Data throughput in MBytes/second was also measured.
Throughput capacity of the initial data copy was 42MBytes/second in local mode and reduced by less than 17% at the maximum link length of 600km, and the timings for the operation of the data replication application increased by less than 33% over this distance.