Is Fibre SAN the ONLY solution for clustering application servers?
Do application servers require an SAN to cluster/load-balance?
[I seem to have stumped my peers on the ColdFusion forums last month with this one. Perhaps a broader audience can help.]
To clarify (and generalize - I won't limit this discussion to ColdFusion, PHP or ASP servers), we're looking to cluster/load-balance our shared server farm. However, the majority of our customers' web sites are not static. They feature dynamic and database-driven content. Sure, we can offload the databases to clustered database servers, but that doesn't solve all of those customer-built applications that write files, for example. If we are to cluster these servers, then those file writes must be mirrored across each cluster member in real-time. Otherwise, server content will quickly go out of sync.
I understand that two servers can share a single SCSI RAID enclosure, but that's insufficient. We'd like to add any number of servers to our cluster, with each of them sharing the same virtual disk. Is a fibre-channel (or copper, for that matter) SAN the only solution?
Any advice is greatly appreciated.
