Today, disaster backup is an important issue, and how to ensure that the data center as soon as possible recovery operations after a certain level of failure and disaster, is essential for some of the business continuity sensitive enterprise.
Disaster backup most use the city off-site disaster recovery. Depending on the user’s business difference, the designed disaster recovery solution is very different. For remote disaster recovery solutions, some host-based or based on storage replication via TCP / IP reliaze offsite backup.
Howere,TCP / IP network is not very stable, may occur packet loss, so to achieve copy need a variety of ways such as fiber optic channels or ATM technology, that can reach the long-distance disaster recovery system, from more than ten kilometers to tens of kilometers or even thousands of kilometers can achieve both disaster recovery system.
This technology we calle it fiber-optic network multiplexing – DWDM
In a long distance SAN environment, because business needs, you must consider disaster recovery. If do not use DWDM, you must use a lot of long fiber cable to relize disaster backup.
But more of the optical fiber will bring the greater the cost. Then do we do not have a good solution to this?
Yes, this is DWDM fiber optic multiplexing (DenseWavelength-Division Multiplexing, high-density multi-work-point filter), according to the WDM development over DWDM technology has been widely used for many years, using DWDM SAN diagram will become like that:
The principles of DWDM principles
As for the Fiber multiplexing , long-distance fiber-optic lines now need only one fiber, just to consider the redundancy, as long as the two fiber. After this, the entire structure has not changed, you can think of that fiber line run multiple fiber you need.
DWDM is how to achieve it? We can look at a schematic:
The DWDM is actually using different wavelengths in a fiber optic line to pass different data, to simulate different channels actually look like different fiber communication. As long as the wavelength is not same, so DWDM casually can multiplexing dozens of channels in a fiber optic line At laboratories can even reuse the thousands of channels.
So with DWDM access to remote storage via SAN becomes very easy, remote RAC is no longer a dream. In fact, through this DWDM technology, and then use the volume replication to disaster recovery technology has been officially in use in the domestic banking institutions. Moreover, the remote RAC, a new disaster recovery plan, which can achieve high availability and Load balancing, and disaster recovery program, also consider using in the company.