Sunday 1 February 2015

When is Server not a Server?

Every serverless school will have at least one server.

This sounds like a contraction - but it's not really. This is because every school using SaaS has a internet connection and this requires a device that links the schools internal network to all those important external services.

This is the internet router and it's a server.

Sitting in a data cabinet or on top of a cupboard it may not look like a server but it will be running an operating system and it will be providing a service to the school in much the same way as a file or print server does. In this case it will be routing packets between two networks in a controlled and secure manner and maybe doing some protocol conversion along the way.

The big difference between this this device and the dusty 'out-of-warranty' pedestal server under the desk is the fact that it only does one thing. The router comes with a predetermined feature set which can be adjusted and tweaked but not extended in any general manner.  Its a one trick pony.

Has your desk got one of these ?

Extending the analogy further the site may have other 'servers' - some acting as firewalls and others as content filters. So a serverless school can have many servers without creating a contradiction, so long as they fulfill a single function and they are called appliances.

Another key characteristic that all appliances share is that any configuration is either replicated, easily backed up or considered disposable. This allows them to make use of low cost local drives rather than more expensive protected storage.

Even in a SaaS school it makes sense to deliver certain services locally. In the case of DHCP this is a technical requirement. In other cases, such a print spooling it might be a design consideration based on simple efficiency.

An on-premise appliance that is designed solely to support SaaS is an interesting concept and does not detract from the serverless approach so long as some basic principals are maintained.
  • The device has a well defined role and is not considered extendable.
  • Any data held locally is disposable or is replicated/saved to cloud storage.
So the answer to the the question is quite obvious..

       When is a server not a server ?
       When its appliance.

Apologies for that.

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