SharePoint 2013 Stretched Farms

At the preview release of SharePoint, stretched farms were not supported.

http://technet.microsoft.com/en-us/library/cc262485(v=office.15).aspx#hwLocServers

This is set to change with recent announcements from MS at least allowing limited support for a stretched farm.  MS it would seem have been doing some testing on performance and capacity boundaries and will support a limited set of stretch farm topologies under the definition of distributed topologies. All of these topologies are based on a prerequisite of minimal (< 1ms) latency between components of the farm.

This is important, as it means:

  • No support for geographical stetched farms, so you cannot span cities and geographies with single farm topology elements
  • Recognition of Support if the logical data center is comprised of one or more physical buildings on a single site.  This is supported providing there is a highly consistent intra-farm latency between the web front-end and database servers of <1ms, 99.9% of the time in one direction over a sustained test period of ten minutes, and at least 1 gigabit per second bandwidth.

If neither of the above satisfy what you are wondering about stretched farms and how you can us one, so you have a client who cannot get the magic 1ms (most people frankly) then you need to look at a fault tolerant architecture – which is what this is about.  Many people confuse stretched farms with an ability to manage Disaster Recovery when in fact it’s about making your platform fault tolerant.  You can read about fault tolerant 2013 architectures here as it is equally important to realize that you can build in fault tolerance without trying to stretch the farm topology between sites:

http://technet.microsoft.com/en-us/library/cc748824.aspx#HAArchitecture