Tuesday01 September 2015

Making a virtual out of necessity

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As belt-tightening continues for the foreseeable future, many practices are finding that cost-saving decisions about replacement of servers can be deferred no longer

Microsoft Server software remains the dominant server software of choice for many practices. The basic Windows server software 2003, and more recently 2008, are periodically updated and new features get added. However, one constant is that the installations are hardware-specific.

The installations also require a high degree of configuration and can be time-consuming to resuscitate following hardware or system failures. It is desirable to achieve a high degree of resilience within the specification of the hardware. Duplicated processors, power supplies and hard disk controllers are common. The inevitable consequence is that the server hardware is expensive.

While built-in hardware redundancy diminishes the likelihood of failure, it cannot rule it out totally. This is where virtualisation starts to come into play. Basically, instead of installing the server software directly on the hardware you first install virtualisation software, such as VMware ESX/ESXi or Microsoft Hyper V, which then allows you to install the server software onto a virtual machine.

The immediate effect is that the server installation becomes specific to a virtual machine rather than the specific hardware. As an identical virtual machine can be created on a wide range of physical hardware the virtualised server can be painlessly run on alternative machines in an emergency. This is made all the easier by the ability of virtualisation software to make snapshots of an installed server on a scheduled basis.

Significant cost savings

But beyond this increase in resilience of individual server installations, virtualisation opens up the possibility of cost savings, as it is possible to install multiple virtual servers on a single physical machine. It is often desirable for performance optimisation, and configuration and maintenance purposes to run different servers on independent operating systems.

Using virtualisation file servers, exchange servers, licence servers, domain controllers and database servers can have individual virtual installations on a single physical server hardware, resulting in significant savings in cost. Obviously the optimum resilience would be achieved by using two suitable servers. Using software such as VMotion on VMware in the event of the failure of one physical server the virtual servers can be configured to automatically migrate to the other hardware.

While adopting virtualisation has obvious appeal, any implementation is worth researching fully. Our experience has been that virtualisation works best with recent full versions of Microsoft server software. Beware the small business server editions, which can result in unsatisfactory implementations as conflicts can arise in attempt to optimise the individual services. It is certainly worth considering as a way forward to renew your servers in 2011.

Merits of cad referencing

A couple of eagle eyed readers have pulled me up on my one-line comparison of Autocad and Vectorworks referencing within the recent review of Autocad for OSX. On reflection I tend to agree with their point of view.

The merits of software features are inextricably linked to how those features are actually used and the deployment of reference files is governed more than most by the cad protocols and procedures that any particular architecture office sets in place. In this context, any comparison of the reference file functionality of different cad programs deserves a wider discourse. Perhaps a future article?

In any event I would always recommend any practice test how software fits its own requirements. Vectorworks has much to be recommended. Straight out of the box it seems particularly capable of producing attractive-looking drawings!

Hugh Davies is a co-founder of IT consultant Lomas Davies.


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