Friday 5 September 2014

The Dilemma of On-Premise Servers.

In a SaaS world what exactly does a local installation do when its no longer handing mail, storing files or running applications?

No doubt it will have some functionality do you really need multiple servers perhaps running VMWare or Hyper-V, network attached storage (NAS), backup hardware and a clean air conditioned server room?

This problem highlights one of the key dilemmas with local infrastructure.

Service cannot be delivered in a reliable way without duplication of resource to remove single points of failure.

This pushes up cost and creates a spiraling relationship of system interdependence that quickly creates complexity. For example it would be technically possible to deliver a school system on a single server running a hypervisor and accessing local storage.The problem is, should any major component in the server fail all services will be lost.  Perhaps a more worryingly situation would be if the server was stolen!

In this case a minimal solution now extends to two servers with backup mechanism which may involve a separate NAS device or tape drive that allows data to be taken off site . However should one server fail, the time to recover data to the remaining server is likely to be unacceptable, so a shared storage system now becomes desirable along with a UPS to maintain power and a clean secure environment to validate the warranty for the tape device and NAS.

So to support even the most basic service levels we are quickly back to a two server configuration with a backup device, shared storage and a secure, clean room.

 This is the second dilemma.

There is no way of designing an on-premise solution that provides a degree of fault tolerance while keeping it simple and cost effective. 

 The problems continue however.

The school now has data and applications stored locally but the users request a method of accessing it remotely so you need to install additional hardware and software to provide a VPN or terminal service facility. The VPN is security risk and so it requires border security checking and enterprise virus protection mechanism. The remote access requirement adds more servers to the solution along with a server for each 3rd party application. These need management and patch control so another server is added to host a service such as Windows Server Update Services (WSUS).

So systems suffer the same problems as hardware. There is no way of designing an on-premise solution that delivers the level of service that a school requires while keeping it simple.

Whatever approach is taken the requirements quickly escalate to the point where you are back where you started.

Even taking a external hosting approach does not solve the problem. Some of the hardware, remote access and resiliency issues are mitigated but the system is still as complex and still needs managing on the same way. Very few of the problems are solved, they are just moved to a different location.

This is the Dilemma of On-Premise Servers.

It can be done  - but only if the local infrastructure acts as a support framework for SaaS.

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