Many organisations are still experimenting with
virtualisation to get the best from their IT infrastructure, but
the Association of Teachers and Lecturers (ATL) has embraced the
technology, and is nearing the end of a virtualisation programme
that began in July 2005.
As reported in Computer Weekly earlier this month, the ATL has
used VMware's ESX Server 2.5 platform to virtualise 17 core
applications. Among these are Microsoft Exchange Server 2003 with
Active Directory, Microsoft SQL Server 2000, Lotus Domino and an
Oracle 9i 10g database.
Shifting these applications into a pool of virtualised computing
resources has enabled the ATL to consolidate its servers at a ratio
of five to one, reducing hardware and maintenance costs in the
process.
The ATL has also gained the ability to recover quickly from
system failures, as it can quickly move running applications
between machines, and in and out of its disaster recovery
environment, using VMware's VMotion tool.
Bernard King, systems architect at the ATL, said this ability
was tested on 15 November last year when an important HP Proliant
G4 server experienced power loss, knocking out the Exchange server.
"During the night it rebooted, so it shut down and switched back on
again in a previous state," said King.
But the ATL's virtual environment meant that within an hour the
IT department had shifted the critical server applications onto
another machine, and located the hardware fault inside the
motherboard.
The server consolidation also means that the ATL now has a pool
of spare servers that it is starting to redeploy for network load
balancing on its website, said King.
The ATL has also found that virtualisation makes more demands on
the storage area network (San), and has begun reorganising the San
to make it bigger and more robust.
"VMware requires a different way to balance the load, as you
have multiple machines accessing the hard disc. So you are
constantly having to restructure the San," said King. The ATL has
added a second San for backup purposes.
One key issue the ATL has been forced to confront is licensing.
Under many licences, applications are tied to particular servers,
so moving them around can break the terms of existing agreements.
This has caused the ATL to shelve moving some systems over to the
virtual environment, including a document management system.
"Licensing can be a sticking point when deciding whether or not
to virtualise. With our document management system, the supplier
was reluctant to support it. They were going to put us on a support
contract that would be more costly so we decided not to virtualise
it," said King.
However, both Microsoft and Oracle have agreed to ATL running
their applications over multiple machines, licensing them per user
rather than per CPU core.
Application support has also changed, because some of the ATL's
suppliers prefer the ATL to send DVDs with virtual machines running
the application to help fix any errors. This was the case with both
Tridian, the ATL's content management supplier, and Verity.
But King and the ATL are far from finished with virtualisation
technology. The plan for this year includes virtualising key
Blackberry servers, an Autonomy Idol system, and 64-bit Exchange
Server 2005.
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