It is common to add components to SANs as specific needs arise, which makes it also typical to have a heterogeneous network with components of varying quality and capability.
Economic reasons may prevent the replacement of older components in a SAN until they fail or become obsolete, but it is still necessary to manage all of the components. Standardizing on one "best-of-breed" vendor for each type of SAN component can minimize the complexity of heterogeneous SANs.
For example, standardizing on one switch vendor for each SAN installation provides the ability to cross-connect the devices for redundancy in the event one switch fails. Such a heterogeneous SAN based on "best-of-breed" devices and a mixture of older and newer components can present significant interoperability and management problems. The best way to avoid these problems that can occur in a heterogeneous (multi-vendor) SAN is to make device interoperability a consideration during the component purchase cycle. Also, you should select a SAN management application that offers a great deal of flexibility and robustness in working with current and forthcoming standards, features and proprietary interfaces of all the major equipment and software vendors.
About the author: Robert Wright is the vice president of software engineering at Connex, Inc.
This was first published in February 2001