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If Jack Sprat ran an IT department

From the thick of it to the thin client of it

By Danny Bradbury, 22 Mar 2016

Moving to thin clients can save you capital and maintenance costs. It’s a brave IT manager that will do it all at once, though. Giving up PCs for smaller devices with simpler specifications represents a big change for administrators, and there may be kinks to work out. In any case, users don’t like disruption, so it’s best to ease them into it. How can you move from fat to lean gradually, to minimize risk?

“Most people will do it piecemeal,” predicted Mark Lomas, IT consultant at Icomm Technologies, which provides computer consulting services to SMBs. In many cases, they may replace PCs with thin clients as they fail or reach the end of their support warranty, he said.

A lot will depend on your hardware refresh cycle. Did you plan on sweating your PCs a lot longer? Are the computers in some departments older than others? This may affect your decision.

Choosing your first users

Companies will probably want to roll out a pilot group of thin clients with a subset of users at the beginning. Choosing a starting point can lead you down several different paths, explained Gunnar Menzel, vice president and chief architect at Capgemini Infrastructure Services.

“Are you starting with a role-based approach, so looking at your sales force, or helpdesk engineers or callcentre advisors?” he asks. “Or are you doing it from a device perspective?”

If you’re piloting thin clients based on user role, then make sure you’ve carved up your user base into distinct types, and that you understand the job requirements for each.

Some user roles might be out on the road a lot of the time, often without quality network access. How are they to access data for Excel remotely? If you give them a tablet, you may need to think about replicating data, which creates security and backup questions. Or you could negotiate a corporate deal with a network service provider to ensure that their thin client connects to the most appropriate and cost-effective network based on their location.

Different thin computing models for different users

How you manage your PC switchover will also depend a lot on your thin client model. It isn’t a binary option. In addition to ‘fat traditional PC clients and thin ones, there’s also ‘thin-fat’, in which a traditional PC is used to access centralized resources.

“Even people with a fat client could find themselves sitting in front of a PC, loading it up and launching their way into a remote desktop environment rather than a local one,” said Lomas.

Setting a PC up as a thin client has to be done properly to avoid confusion, though. PC users will quickly lose focus if they’re logging into a local PC and then having to find and log into another virtual desktop somewhere else.

Administrators can load a thin client operating system onto a fat client PC designed to boot minimally and then drop them straight into a hosted session. Just as with thin client hardware, that could be provided using session virtualization, via something like Citrix XenApp or Microsoft’s Remote Desktop Services, in which one Windows instance is virtualized and served up to multiple users.

The alternative to session virtualization is virtual desktop infrastructure, in which each user is given their own full operating system in a virtual machine. VDI can be a lot less tolerant of bandwidth and latency issues, and typically requires a larger up-front investment in time and money.

“I’ve usually only seen VDI take off in larger enterprise organizations that can afford to do this, and even there it only takes off in part of the business,” Lomas said. Session virtualization is easier to provision in many cases.

There is another way to support a fat client without switching it over to a thin client device. Application virtualization involves streaming application code in small segments down to the client, which runs it without installing it. That’s doable on PCs, but thin clients would need sufficient local resources to run the streamed code. It’s not really a ‘zero client’ option.

Application virtualization also isolates the applications from the underlying operating system in the system image. This can make it easier to support employees using different client types at the back end, by creating different sets of applications to be loaded with each user’s profile.

Some power users may need to retain fat PCs or suitably-equipped thin clients so that they can use specific software. In these cases, virtualized applications can give them what they need while scaling down client capabilities as appropriate.

Learn as you go

A gradual approach to thin client migration gives you some valuable time to tweak your operations. That’s important, because you may well run into problems along the way. Suddenly moving everyone to thin clients at once could result in boot storms, as all of your employees arrive on Monday morning and try to kick off virtual desktops at once.

If you suffer from a boot storm, you’ll know it pretty quickly, but other problems with thin client computing can be devilishly hard to pin down. Menzel was once moving a company to thin clients. He deployed a mixed load, with around 20 per cent fat clients for high-powered users, and thin clients for the rest.

Along the way, he ran into bandwidth problems at random times that he couldn’t understand at first.

“Applications worked well on the thin clients, but on the fat clients, they were sucking in significant amounts of data that the team thought was coming from a local store, but which came from the centre,” he said. Once they identified that, they could fix the problem, but it took three months to track the issue down.

Problems like these can arise, particularly when using distributed applications, with some components running locally and some from a central point, Menzel explained. Understanding this stuff requires some specific skills, and these should be in place before you start.

A staged approach to thin client deployment can be beneficial to IT admins, especially those without prior experience. It’s also a good way to compartmentalise your users, giving them client hardware and software delivery options that meet their particular requirements. It can help you to limit mistakes to small groups, and to tweak the project as you go along. When you’re dealing with something as far-reaching as end user desktop tools, it makes sense to do it in small steps. ®

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