IP tops the list of readers's SAN extension choices in this month's Byte and Switch poll, though it's not the only method favored.
Readers apparently disagree with our February report that found IP isnt quite ready to unseat Sonet/SDH as a SAN extension technology, owing to its limitations for data mirroring (see Report: Sonet's Tops for SAN Extension).
Still, only 24 percent of poll respondents say IP is the sole transport method to extend SANs. Sonet/SDH and CWDM and/or DWDM are each being used by 12 percent of respondents, while one-third of those polled use a combination of wavelengths, Sonet/SDH, and IP.
On the face of it, these results indicate users are deploying different techniques for different needs -- IP use for backup, Sonet for average accessibility, and WDM for continuous uptime (see Report: SANs and the City).
Other results seem to bear this out. Of those polled, 21 percent said they're using SAN extension for backup, while 26 percent of those polled said they use it for a combination of synchronous and asynchronous data mirroring. Eighteen percent use it for asynchronous data mirroring, and 15 percent for synchronous mirroring only. Twenty-one percent find other uses for SAN extension.