The factor about clouds is that they will change form whilst you watch them. So it’s with the Google Cloud, and the steering we supplied InfoWorld readers two years in the past about making a SQL Server failover cluster occasion (FCI) within the Google Cloud not displays greatest practices.
The steering supplied then nonetheless works, however adjustments within the Google Cloud imply that organizations wanting a cloud-based infrastructure supporting SQL Server at 99.99 p.c availability ranges now have higher, extra environment friendly methods to create SQL Server FCIs. The fundamentals of these new pointers may be present in Google’s on-line directions for configuring a SQL Server FCI.
Google’s present steering is evident and simple to comply with. But organizations severe about 99.99 p.c ranges of availability ought to comply with these pointers solely up to some extent. As outlined within the documentation, the FCI depends on shared storage configured utilizing Microsoft’s Storage Spaces Direct choice, and that creates an availability Catch-22.
The problem is that this: Microsoft pointers for Storage Spaces Direct require all of the VMs and storage to reside in the identical knowledge middle, and it’s not clear that an FCI configured within the method outlined by Google complies with this requirement. The Google documentation directs you to position the VMs in a number of zones throughout the Google Cloud, and if these zones will not be the identical knowledge middle then you definitely’re making a Storage Spaces Direct configuration that’s unsupported.
The Catch-22 is that if you happen to configure the FCI so that every one the VMs are in the identical knowledge middle, and thus compliant with Storage Spaces Direct pointers, your FCI doesn’t qualify for Google’s excessive availability SLA (which requires that a minimum of one VM within the SQL Server FCI reside in a distinct zone). If the entire knowledge middle goes offline (and entire knowledge facilities have performed so), your entire FCI can even go offline.
